diff --git a/easybuild/toolchains/compiler/llvm.py b/easybuild/toolchains/compiler/llvm.py
new file mode 100644
index 0000000000..895b386791
--- /dev/null
+++ b/easybuild/toolchains/compiler/llvm.py
@@ -0,0 +1,187 @@
+##
+# Copyright 2013-2025 Ghent University
+#
+# This file is triple-licensed under GPLv2 (see below), MIT, and
+# BSD three-clause licenses.
+#
+# This file is part of EasyBuild,
+# originally created by the HPC team of Ghent University (http://ugent.be/hpc/en),
+# with support of Ghent University (http://ugent.be/hpc),
+# the Flemish Supercomputer Centre (VSC) (https://www.vscentrum.be),
+# Flemish Research Foundation (FWO) (http://www.fwo.be/en)
+# and the Department of Economy, Science and Innovation (EWI) (http://www.ewi-vlaanderen.be/en).
+#
+# https://github.com/easybuilders/easybuild
+#
+# EasyBuild is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation v2.
+#
+# EasyBuild is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with EasyBuild.  If not, see <http://www.gnu.org/licenses/>.
+##
+"""
+EasyBuild support for Clang + Flang compiler toolchain.
+
+Authors:
+
+* Dmitri Gribenko (National Technical University of Ukraine "KPI")
+* Davide Grassano (CECAM EPFL)
+"""
+
+from easybuild.tools import LooseVersion
+import easybuild.tools.systemtools as systemtools
+from easybuild.tools.toolchain.compiler import Compiler, DEFAULT_OPT_LEVEL
+from easybuild.tools.toolchain.toolchain import SYSTEM_TOOLCHAIN_NAME
+
+TC_CONSTANT_LLVM = "LLVM"
+
+
+class LLVM(Compiler):
+    """Compiler toolchain with Clang and GFortran compilers."""
+    # NAME = 'LLVMcore'
+    # COMPILER_MODULE_NAME = [NAME]
+    COMPILER_FAMILY = TC_CONSTANT_LLVM
+    SUBTOOLCHAIN = SYSTEM_TOOLCHAIN_NAME
+
+    # List of flags that are supported by Clang but not yet by Flang and should be filtered out
+    # The element of the list are tuples with the following structure:
+    # (min_version, max_version, [list of flags])
+    # Where min_version and max_version are strings representing a left-inclusive and right-exclusive version range,
+    # [min_version, max_version) respectively.
+    # This is used to specify general `clang`-accepted flags and remove them from `flang` compiler flags if
+    # not supported for a particular version of LLVM
+    FLANG_UNSUPPORTED_VARS = [
+        ('19', '21', [
+            '-fmath-errno', '-fno-math-errno',
+            '-fslp-vectorize',
+            '-fvectorize', '-fno-vectorize',
+            '-fno-unsafe-math-optimizations',
+        ])
+    ]
+
+    FORTRAN_FLAGS = ['FCFLAGS', 'FFLAGS', 'F90FLAGS']
+
+    COMPILER_UNIQUE_OPTS = {
+        'loop-vectorize': (False, "Loop vectorization"),
+        'basic-block-vectorize': (False, "Basic block vectorization"),
+
+        # https://github.com/madler/zlib/issues/856
+        'lld_undefined_version': (True, "-Wl,--undefined-version - Allow unused version in version script"),
+        'no_unused_args': (
+            True,
+            (
+                "-Wno-unused-command-line-argument - Avoid some failures in CMake correctly recognizing "
+                "feature due to linker warnings"
+            )
+        ),
+        'no_int_conversion_error': (
+            True,
+            "-Wno-error=int-conversion - Avoid some failures that are normally ignored by GCC"
+        ),
+    }
+
+    COMPILER_UNIQUE_OPTION_MAP = {
+        'unroll': '-funroll-loops',
+        'loop-vectorize': ['-fvectorize'],
+        'basic-block-vectorize': ['-fslp-vectorize'],
+        'optarch': '',
+        # 'optarch': '-march=native',
+        # Clang's options do not map well onto these precision modes.  The flags enable and disable certain classes of
+        # optimizations.
+        #
+        # -fassociative-math: allow re-association of operands in series of floating-point operations, violates the
+        # ISO C and C++ language standard by possibly changing computation result.
+        # -freciprocal-math: allow optimizations to use the reciprocal of an argument rather than perform division.
+        # -fsigned-zeros: do not allow optimizations to treat the sign of a zero argument or result as insignificant.
+        # -fhonor-infinities: disallow optimizations to assume that arguments and results are not +/- Infs.
+        # -fhonor-nans: disallow optimizations to assume that arguments and results are not +/- NaNs.
+        # -ffinite-math-only: allow optimizations for floating-point arithmetic that assume that arguments and results
+        # are not NaNs or +-Infs (equivalent to -fno-honor-nans -fno-honor-infinities)
+        # -funsafe-math-optimizations: allow unsafe math optimizations (implies -fassociative-math, -fno-signed-zeros,
+        # -freciprocal-math).
+        # -ffast-math: an umbrella flag that enables all optimizations listed above, provides preprocessor macro
+        # __FAST_MATH__.
+        #
+        # Using -fno-fast-math is equivalent to disabling all individual optimizations, see
+        # http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/Tools.cpp?view=markup (lines 2100 and following)
+        #
+        # 'strict', 'precise' and 'defaultprec' are all ISO C++ and IEEE complaint, but we explicitly specify details
+        # flags for strict and precise for robustness against future changes.
+        'strict': ['-fno-fast-math'],
+        'precise': ['-fno-unsafe-math-optimizations'],
+        'defaultprec': [],
+        'loose': ['-ffast-math', '-fno-unsafe-math-optimizations'],
+        'veryloose': ['-ffast-math'],
+        'vectorize': {False: '-fno-vectorize', True: '-fvectorize'},
+        DEFAULT_OPT_LEVEL: ['-O2'],
+
+        'lld_undefined_version': ['-Wl,--undefined-version'],
+        'no_unused_args': ['-Wno-unused-command-line-argument'],
+        'no_int_conversion_error': ['-Wno-error=int-conversion'],
+    }
+
+    COMPILER_OPTIONS = [
+        'lld_undefined_version',
+    ]
+
+    # Options only available for Clang compiler
+    COMPILER_C_OPTIONS = [
+        'no_unused_args',
+        'no_int_conversion_error'
+    ]
+
+    # Options only available for Flang compiler
+    COMPILER_F_OPTIONS = []
+
+    # used when 'optarch' toolchain option is enabled (and --optarch is not specified)
+    COMPILER_OPTIMAL_ARCHITECTURE_OPTION = {
+        (systemtools.POWER, systemtools.POWER): '-mcpu=native',  # no support for march=native on POWER
+        (systemtools.POWER, systemtools.POWER_LE): '-mcpu=native',  # no support for march=native on POWER
+        (systemtools.X86_64, systemtools.AMD): '-march=native',
+        (systemtools.X86_64, systemtools.INTEL): '-march=native',
+    }
+    # used with --optarch=GENERIC
+    COMPILER_GENERIC_OPTION = {
+        (systemtools.RISCV64, systemtools.RISCV): '-march=rv64gc -mabi=lp64d',  # default for -mabi is system-dependent
+        (systemtools.X86_64, systemtools.AMD): '-march=x86-64 -mtune=generic',
+        (systemtools.X86_64, systemtools.INTEL): '-march=x86-64 -mtune=generic',
+    }
+
+    COMPILER_CC = 'clang'
+    COMPILER_CXX = 'clang++'
+    COMPILER_C_UNIQUE_OPTIONS = []
+
+    COMPILER_F77 = 'flang'
+    COMPILER_F90 = 'flang'
+    COMPILER_FC = 'flang'
+    COMPILER_F_UNIQUE_OPTIONS = []
+
+    LIB_MULTITHREAD = ['pthread']
+    LIB_MATH = ['m']
+
+    def _set_compiler_flags(self):
+        super()._set_compiler_flags()
+
+        unsupported_fortran_flags = None
+        for v_min, v_max, flags in self.FLANG_UNSUPPORTED_VARS:
+            if LooseVersion(self.version) >= LooseVersion(v_min) and LooseVersion(self.version) < LooseVersion(v_max):
+                unsupported_fortran_flags = flags
+                break
+        else:
+            self.log.debug("No unsupported flags found for LLVM version %s", self.version)
+
+        if unsupported_fortran_flags is not None:
+            self.log.debug(
+                f"Ensuring usupported Fortran flags `{unsupported_fortran_flags}` are removed from variables"
+            )
+            for key, lst in self.variables.items():
+                if key not in self.FORTRAN_FLAGS:
+                    continue
+                for item in lst:
+                    item.try_remove(unsupported_fortran_flags)
diff --git a/easybuild/toolchains/lfbf.py b/easybuild/toolchains/lfbf.py
new file mode 100644
index 0000000000..0c4fa89289
--- /dev/null
+++ b/easybuild/toolchains/lfbf.py
@@ -0,0 +1,44 @@
+##
+# Copyright 2021-2025 Ghent University
+#
+# This file is part of EasyBuild,
+# originally created by the HPC team of Ghent University (http://ugent.be/hpc/en),
+# with support of Ghent University (http://ugent.be/hpc),
+# the Flemish Supercomputer Centre (VSC) (https://www.vscentrum.be),
+# Flemish Research Foundation (FWO) (http://www.fwo.be/en)
+# and the Department of Economy, Science and Innovation (EWI) (http://www.ewi-vlaanderen.be/en).
+#
+# https://github.com/easybuilders/easybuild
+#
+# EasyBuild is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation v2.
+#
+# EasyBuild is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with EasyBuild.  If not, see <http://www.gnu.org/licenses/>.
+##
+"""
+EasyBuild support for gfbf compiler toolchain (includes GCC, FlexiBLAS and FFTW)
+
+Authors:
+
+* Kenneth Hoste (Ghent University)
+* Bart Oldeman (McGill University, Calcul Quebec, Compute Canada)
+* Davide Grassano (CECAM EPFL)
+"""
+
+from easybuild.toolchains.llvm import LLVMtc
+from easybuild.toolchains.fft.fftw import Fftw
+from easybuild.toolchains.linalg.flexiblas import FlexiBLAS
+
+
+class Lfbf(LLVMtc, FlexiBLAS, Fftw):
+    """Compiler toolchain with GCC, FlexiBLAS and FFTW."""
+    NAME = 'lfbf'
+    SUBTOOLCHAIN = LLVMtc.NAME
+    OPTIONAL = True
diff --git a/easybuild/toolchains/lfoss.py b/easybuild/toolchains/lfoss.py
new file mode 100644
index 0000000000..584c48c0b7
--- /dev/null
+++ b/easybuild/toolchains/lfoss.py
@@ -0,0 +1,90 @@
+##
+# Copyright 2013-2025 Ghent University
+#
+# This file is part of EasyBuild,
+# originally created by the HPC team of Ghent University (http://ugent.be/hpc/en),
+# with support of Ghent University (http://ugent.be/hpc),
+# the Flemish Supercomputer Centre (VSC) (https://www.vscentrum.be),
+# Flemish Research Foundation (FWO) (http://www.fwo.be/en)
+# and the Department of Economy, Science and Innovation (EWI) (http://www.ewi-vlaanderen.be/en).
+#
+# https://github.com/easybuilders/easybuild
+#
+# EasyBuild is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation v2.
+#
+# EasyBuild is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with EasyBuild.  If not, see <http://www.gnu.org/licenses/>.
+##
+"""
+EasyBuild support for foss compiler toolchain (includes GCC, OpenMPI, OpenBLAS, LAPACK, ScaLAPACK and FFTW).
+
+Authors:
+
+* Kenneth Hoste (Ghent University)
+* Davide Grassano (CECAM EPFL)
+"""
+from easybuild.toolchains.lompi import Lompi
+from easybuild.toolchains.lfbf import Lfbf
+from easybuild.toolchains.lolf import Lolf
+from easybuild.toolchains.fft.fftw import Fftw
+from easybuild.toolchains.linalg.flexiblas import FlexiBLAS
+from easybuild.toolchains.linalg.scalapack import ScaLAPACK
+from easybuild.tools import LooseVersion
+
+
+class LFoss(Lompi, FlexiBLAS, ScaLAPACK, Fftw):
+    """Compiler toolchain with GCC, OpenMPI, FlexiBLAS, ScaLAPACK and FFTW."""
+    NAME = 'lfoss'
+    SUBTOOLCHAIN = [
+        Lompi.NAME,
+        Lolf.NAME,
+        Lfbf.NAME
+    ]
+
+    def __init__(self, *args, **kwargs):
+        """Toolchain constructor."""
+        super(LFoss, self).__init__(*args, **kwargs)
+
+        # need to transform a version like '2018b' with something that is safe to compare with '2019'
+        # comparing subversions that include letters causes TypeErrors in Python 3
+        # 'a' is assumed to be equivalent with '.01' (January), and 'b' with '.07' (June) (good enough for this purpose)
+        version = self.version.replace('a', '.01').replace('b', '.07')
+
+        self.looseversion = LooseVersion(version)
+
+        constants = ('BLAS_MODULE_NAME', 'BLAS_LIB', 'BLAS_LIB_MT', 'BLAS_FAMILY',
+                     'LAPACK_MODULE_NAME', 'LAPACK_IS_BLAS', 'LAPACK_FAMILY')
+
+        for constant in constants:
+            setattr(self, constant, getattr(FlexiBLAS, constant))
+
+    def banned_linked_shared_libs(self):
+        """
+        List of shared libraries (names, file names, paths) which are
+        not allowed to be linked in any installed binary/library.
+        """
+        res = []
+        res.extend(Lompi.banned_linked_shared_libs(self))
+        res.extend(FlexiBLAS.banned_linked_shared_libs(self))
+        res.extend(ScaLAPACK.banned_linked_shared_libs(self))
+        res.extend(Fftw.banned_linked_shared_libs(self))
+
+        return res
+
+    def is_deprecated(self):
+        """Return whether or not this toolchain is deprecated."""
+
+        # lfoss toolchains older than 2023b should not exist (need GCC >= 13)
+        if self.looseversion < LooseVersion('2023'):
+            deprecated = True
+        else:
+            deprecated = False
+
+        return deprecated
diff --git a/easybuild/toolchains/llvm.py b/easybuild/toolchains/llvm.py
new file mode 100644
index 0000000000..ac1d5c8695
--- /dev/null
+++ b/easybuild/toolchains/llvm.py
@@ -0,0 +1,45 @@
+##
+# Copyright 2013-2025 Ghent University
+#
+# This file is triple-licensed under GPLv2 (see below), MIT, and
+# BSD three-clause licenses.
+#
+# This file is part of EasyBuild,
+# originally created by the HPC team of Ghent University (http://ugent.be/hpc/en),
+# with support of Ghent University (http://ugent.be/hpc),
+# the Flemish Supercomputer Centre (VSC) (https://www.vscentrum.be),
+# Flemish Research Foundation (FWO) (http://www.fwo.be/en)
+# and the Department of Economy, Science and Innovation (EWI) (http://www.ewi-vlaanderen.be/en).
+#
+# https://github.com/easybuilders/easybuild
+#
+# EasyBuild is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation v2.
+#
+# EasyBuild is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with EasyBuild.  If not, see <http://www.gnu.org/licenses/>.
+##
+"""
+EasyBuild support for Clang + Flang compiler toolchain.
+
+Authors:
+
+* Davide Grassano (CECAM EPFL)
+"""
+
+from easybuild.toolchains.gcccore import GCCcore
+from easybuild.toolchains.compiler.llvm import LLVM
+from easybuild.tools.toolchain.toolchain import SYSTEM_TOOLCHAIN_NAME
+
+
+class LLVMtc(LLVM):
+    """Compiler toolchain with Clang and Flang compilers."""
+    NAME = 'LLVMtc'  # Using `...tc` to distinguish toolchain from package
+    COMPILER_MODULE_NAME = [NAME]
+    SUBTOOLCHAIN = [GCCcore.NAME, SYSTEM_TOOLCHAIN_NAME]
diff --git a/easybuild/toolchains/lolf.py b/easybuild/toolchains/lolf.py
new file mode 100644
index 0000000000..a9509a6383
--- /dev/null
+++ b/easybuild/toolchains/lolf.py
@@ -0,0 +1,44 @@
+##
+# Copyright 2013-2025 Ghent University
+#
+# This file is part of EasyBuild,
+# originally created by the HPC team of Ghent University (http://ugent.be/hpc/en),
+# with support of Ghent University (http://ugent.be/hpc),
+# the Flemish Supercomputer Centre (VSC) (https://www.vscentrum.be),
+# Flemish Research Foundation (FWO) (http://www.fwo.be/en)
+# and the Department of Economy, Science and Innovation (EWI) (http://www.ewi-vlaanderen.be/en).
+#
+# https://github.com/easybuilders/easybuild
+#
+# EasyBuild is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation v2.
+#
+# EasyBuild is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with EasyBuild.  If not, see <http://www.gnu.org/licenses/>.
+##
+"""
+EasyBuild support for golf compiler toolchain (includes GCC, OpenBLAS, LAPACK, and FFTW).
+
+Authors:
+
+* Kenneth Hoste (Ghent University)
+* Bart Oldeman (McGill University, Calcul Quebec, Compute Canada)
+* Davide Grassano (CECAM EPFL)
+"""
+
+from easybuild.toolchains.llvm import LLVMtc
+from easybuild.toolchains.fft.fftw import Fftw
+from easybuild.toolchains.linalg.openblas import OpenBLAS
+
+
+class Lolf(LLVMtc, OpenBLAS, Fftw):
+    """Compiler toolchain with LLVM, OpenBLAS, and FFTW."""
+    NAME = 'lolf'
+    SUBTOOLCHAIN = LLVMtc.NAME
+    OPTIONAL = True
diff --git a/easybuild/toolchains/lompi.py b/easybuild/toolchains/lompi.py
new file mode 100644
index 0000000000..ed06cb3dd6
--- /dev/null
+++ b/easybuild/toolchains/lompi.py
@@ -0,0 +1,60 @@
+##
+# Copyright 2012-2025 Ghent University
+#
+# This file is part of EasyBuild,
+# originally created by the HPC team of Ghent University (http://ugent.be/hpc/en),
+# with support of Ghent University (http://ugent.be/hpc),
+# the Flemish Supercomputer Centre (VSC) (https://www.vscentrum.be),
+# Flemish Research Foundation (FWO) (http://www.fwo.be/en)
+# and the Department of Economy, Science and Innovation (EWI) (http://www.ewi-vlaanderen.be/en).
+#
+# https://github.com/easybuilders/easybuild
+#
+# EasyBuild is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation v2.
+#
+# EasyBuild is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with EasyBuild.  If not, see <http://www.gnu.org/licenses/>.
+##
+"""
+EasyBuild support for lompi compiler toolchain (includes LLVM and OpenMPI).
+
+Authors:
+
+* Kenneth Hoste (Ghent University)
+* Davide Grassano (CECAM EPFL)
+"""
+from easybuild.tools import LooseVersion
+import re
+
+from easybuild.toolchains.llvm import LLVMtc
+from easybuild.toolchains.mpi.openmpi import OpenMPI
+
+
+class Lompi(LLVMtc, OpenMPI):
+    """Compiler toolchain with GCC and OpenMPI."""
+    NAME = 'lompi'
+    SUBTOOLCHAIN = LLVMtc.NAME
+
+    def is_deprecated(self):
+        """Return whether or not this toolchain is deprecated."""
+        # need to transform a version like '2018b' with something that is safe to compare with '2019'
+        # comparing subversions that include letters causes TypeErrors in Python 3
+        # 'a' is assumed to be equivalent with '.01' (January), and 'b' with '.07' (June) (good enough for this purpose)
+        version = self.version.replace('a', '.01').replace('b', '.07')
+
+        deprecated = False
+
+        # make sure a non-symbolic version (e.g., 'system') is used before making comparisons using LooseVersion
+        if re.match('^[0-9]', version):
+            # lompi toolchains older than 2023b should not exist  (need GCC >= 13)
+            if LooseVersion(version) < LooseVersion('2023'):
+                deprecated = True
+
+        return deprecated
diff --git a/test/framework/easyconfigversion.py b/test/framework/easyconfigversion.py
index 59cf051a42..68c4aa1b07 100644
--- a/test/framework/easyconfigversion.py
+++ b/test/framework/easyconfigversion.py
@@ -190,9 +190,10 @@ def test_parser_toolchain_regex(self):
                 self.assertEqual(tcversop.as_dict(), as_dict)
 
             # only accept known toolchain names
+            RANDOM_BIT = 'ShouldNotMatch___'
             fail_tests = [
-                "x%s >= 1.2.3" % tc,
-                "%sx >= 1.2.3" % tc,
+                f"{RANDOM_BIT}{tc} >= 1.2.3",
+                f"{tc}{RANDOM_BIT} >= 1.2.3",
                 "foo",
                 ">= 1.2.3",
             ]
@@ -205,6 +206,7 @@ def test_parser_toolchain_regex(self):
     def test_toolchain_versop_test(self):
         """Test the ToolchainVersionOperator test"""
         _, tcs = search_toolchain('')
+        RANDOM_BIT = 'ShouldNotMatch___'
         tc_names = [x.NAME for x in tcs]
         for tc in tc_names:  # test all known toolchain names
             # test version expressions with optional version operator
@@ -213,8 +215,8 @@ def test_toolchain_versop_test(self):
                     (tc, '1.2.3', True),  # version ok, name ok
                     (tc, '1.2.4', True),  # version ok, name ok
                     (tc, '1.2.2', False),  # version not ok, name ok
-                    ('x' + tc, '1.2.3', False),  # version ok, name not ok
-                    ('x' + tc, '1.2.2', False),  # version not ok, name not ok
+                    (RANDOM_BIT + tc, '1.2.3', False),  # version ok, name not ok
+                    (RANDOM_BIT + tc, '1.2.2', False),  # version not ok, name not ok
                 )),
             ]
             for txt, subtests in tests: