Introducing my LEGO Parts Guide, which is powered by images exported from LDraw.

[Gerald Lasser]

Hm, on some occasions (even rarer than different colors) "unofficial" lego parts appear, including
-mismolds
-mold variants
-unreleased development molds
(but i guess thats too "special" to be included here)

But those are not Q-Parts. Q-Parts are standard parts with colours only available for the Legoland model builders