This is probably going to get moved soon or locked, but here's my advice.
First, guess what you think you would pay for each player in the open market if you do not decide to keep them. For example, if Aaron Rodgers goes back into the pool, will you expect him to get bidded up to $100 or $80? I would only consider keeping players who you can keep for under the expected market value.
Off the bat, I think AJ Green, Lesean McCoy, Lamar Miller, and Randall Cobb are top candidates, but it depends on your league and how you think the other teams will value the players.