Wheres a good place to get renders to make signatures and junk out of?

I know only one
and thats'

Planetrenders

anyone got any others?

Planetrenders is really the best one IMO but there are some other ones too, like Gamerenders comes to mind. Try searching Google with "Graphic render sites" or something like that.

or you can simply make your own
imo, making your own is much better since there are an unlimited variety to chose from..