ClickMorph lets you alt-click to morph with iMorph or jMorph
It's not standalone, you still need to load the morpher first

Install

• Download the latest release zip for Classic or Retail
• Unpack ClickMorph and ClickMorphData into your addons folder:
  C:\Program Files (x86)\World of Warcraft\_classic_\Interface\AddOns

Features

Videos: https://streamable.com/m601s (Classic), https://streamable.com/5rlll (Retail)

• Morph from unlocked Mounts and Appearances (Wardrobe) tab
• Morph from the inspect window and item links/containers
• Supports AtlasLoot Classic, MogIt and Taku's Morph Catalog
• Open the GUI with /clickmorph or /cm
• Automatically remorph on inject/relog (iMorph)

Credits to Icesythe7 for originally developing the addon.