I'm planning a game where different characters come from different time periods and cultures, and I'm using different source books to provide different rules for each character. The general idea is we can all play without knowing really what anyone else can do. So far I've found books for the victorian era and traditional fantasy but, with the exception of d20 star wars and d20 modern, I've not found much for futuristic settings and one of my players is looking to play something near-future.
Are there any books you know of that I can use for ideas/rules/feats/equipment etc? I'm not too bothered about the balance stuff as the players are all fairly happy to work that out as we play and the book doesn't have to be all great, just have bits that I can use in isolation. If that's just a feat or some gear, fine. If it's new classes and a tech system for building gadgets or something, even better. I'm open to any books by any publishers so pretty much anything d20 is game. Thanks.