"Copy of (2)..[name of vst]

I've succeeded in accidentally creating such (short-cut) copies when I've operated with Ctrl-drag or selecting items to move or copy them.
When your finger slips for a fraction of a second you may inadvertedly create copies of what you intended to move. Some mouse-types are much more unstable in that sense than others.

To be shure, check if they are only short-cut copies or copies of the actual VST .dll. Both are possible. In both cases, though, you can delete the copy.