The Ruby Library Depot is a great archive of SU’s plugin history. BUT don’t assume all plugins stored there will work in the latest versions of SU.
With every version of SU, the Ruby environment changes.
If you are still getting error messages, then you did not get rid of everything as the errors may be referring to stuff that should be in specific folders accessible by the plugins (for example.)
The 3D Warehouse problem has been fixed, though you may need to manually remove a cookie…
Before helping you locate the most recent download sites, I know I would rather get you to eliminate the cause of the error messages from all the outdated plugins you already added.