LPJ Design on rpgnow has a large number of D20M based pdfs. I picked up The Little Black Drug Book, Dope Fiends, Modern Chemistry and Modern Maladies for Gamma World (drugs and diseases should be used in a serious GW setting). All of them are well written (esp the latter two- Neil knows how to puts words to paper) and the only downside is there are no tables of content- not that it really matters for short pdfs.
And I second the 2 22 talent trees from Bloodstone. Some are meh, but some are very useful.
And I second the 2 22 talent trees from Bloodstone. Some are meh, but some are very useful.