How about content by WotC designers in third party products? Bruce Cordell designed 3.5e psionics, and also wrote a 3rd party supplement called Hyperconscious. Most people that like psionics consider Hyperconscious valid for the table.

I think you have to look at these products on a case by case basis. Most of the Dragonlance products are fine for inclusion at the table, although reserves of strength may have to be banned.

I haven't delved deeply into Kingdoms of Kalamar, but what I have seen I did not like in terms of design or balance.

Dragon Magazine gets bagged quite a lot and what to include or exclude from Dragon Magazine requires discretion. In my opinion there is some great content there. The mage feats from Dragon Magazine #359 are great and it would be a shame if they were excluded from a table just because it came from Dragon Magazine.