Had the same issue with tracking imported DWGs. In my defence, it’s not my model!
For those still looking for a solution, I’m afraid you will need an addin. This is because Revit will convert each DWG you import into a family instance. To define this instance, it will also generate a family type, which is what we see under VG > Imported Categories and one day will desperately try to delete!
Here’s the issue: to remove the family type of a DWG, we need to find and delete all of its instances in the model, then Purge Unused. This is easier said than done in big models with hundreds of views like mine!
Previous posts suggested addins to speed up this process. The one mpwuzhere mentioned is an extensive set of tools & I was looking for a long term simple solution without paying that much, so tried Model Review instead (Thanks RDAOU!). However, even Model Review didn’t help me much because I wanted to purge SOME, not ALL imported DWGs! I also needed to visually check each DWG in its view before deciding to remove it.
Ended up using DWG Explorer because it does exactly what I need. It also allows directly deleting DWG types from Imported Categories!
https://apps.autodesk.com/RVT/en/Detail/Index?id=3030640795772631843&appLang=en&os=Win64
Does anyone have a better solution?