The StashVertexGroup addon makes it a little bit easier to work with vertex groups in Blender. Its main function is creating a copy ('stash') of a vertex group at a certain stage, to be restored if something goes wrong with its modification (as it often does ;) and this without having to undo all the work done beside that upon this particular vertex group.

The 'stashed vertex group' can also be exported and imported as a .json file, making it easy to work with vertex groups between blender files and keep versions of the same vertex group at hand. This can be extremely helpful for models like the ones from Human Generator - just import that forearm twist vertex group you made the last time or reuse that tedious vertex selection.

A video demonstration of the functionality:

UPDATES:
v1.0 - Initial release.

v1.0.1 - Minor fixes:

• using " in comment input field now works - (renames to ').
• 4x spaces instead of tabs in .json for compatibility.

v1.1.0 - Additions:

• a better comment editing system
• a cleanup feature (clean 'low influence' vertices from the stashed vertex group)
• export the active or all vertex groups in .json format (to be imported just like the stashes)
• some workflow choices in preferences

v1.2.0 - Additions:

• Import multiple vertex groups at once in the .json format.
• UI changes for simplification.

This addon was made with the help of Serpens (and Blender Python API Docs of course :)