Attached Link: http://www.sharecg.com/v/29080/3D-Model/Symbols

Les, Spacebones' Timesavers series should give you more raw material than you can ever handle. The picture above shows only one third of one of his invaluable sets.

He says they're unrestricted use, but if you'd prefer to ask him he's approachable and I'm sure would give permission.