Marking meshes as "to remove"/Generic mesh tagging system

[KaptainMicila]

What is it that you want to do that isn't currently possible?
An expansion of the "Copy reference shape into output" feature.
Currently it's only possible to tag a mesh as "reference": I would like this feature expanded to include something like "meshes to remove on project unload".

Request the feature
I'd like to right click a mesh, and have an entry in the dropdown menu that works like this:

• Mark mesh as:
  • Reference
  • "To remove on project unload"

Tagging meshes as "useless" could be helpful to identify sliders that are also not useful to the project.