Here are the Baseball cards to trade.
Here are the Basketball cards to trade.
Here are the Football cards to trade.
Here are the Hockey cards to trade.
Here are the Racing / Wrestling cards to trade.
Baseball - Joel Zumaya / Armando Galarraga
Basketball - Chauncey Billups / Tayshaun Prince / Jason Maxiell
Football - Barry Sanders / Roy Williams (WR)
Hockey - Steve Yzerman / Pavel Datsyuk / Chris Osgood / Henrik Zetterberg / Nicklas Lidstrom

I also trade for ANY Detroit card from any sport, as long as they are in uniform for that year.
I am really looking to trade for the 95-96 Be A Player Wayne Gretzky Auto S99, along with the Mike Richter mail-in card from that same year, to complete my set.
I trade mostly thru this site : Sports Card Forum
Once I get a request for a specific player I create a doc and will post them up here, with what I have left to trade for that specific player. Here goes that list: