I think I can help out with this one...
.V3M files are 3D content that can be imported into any Vectric Software that can make use of 3D content. These would have been included with VCarve Desktop/Pro and Aspire or downloaded from Design and Make.
.3Dclip files can only be opened in Aspire and can contain a single piece of 3D content or a group of 3D content. These would have been included with your purchase of Aspire or have been exported from Aspires component tree (a feature only found in Aspire).
Sometimes you will have V3Ms that look like 3Dclip files but they are different in that the .3Dclip file might have a group of components that you can ungroup and mess about with.
As for the .vclipp files they are there for the software to look at and sort out what content you may or may not have downloaded from your V&Co Customer portal account. When you open up your Clipart tab in your software, if you see a piece of clipart that needs to be downloaded that appears because of the .vclipp file. If your software can't find the associated .v3m, .3Dclip, .crv or .crv3D file that matches the .vclipp file then you see that thumbnail in the clipart browser. They are small files so I would just leave them... but if you do choose to delete them then you won't know what clipart you are entitled unless you refresh your clipart browser (done via the cloud or refresh icon in the clipart browser).
Hope that helps...
Todd Bailey | Design and Make