Essentially, there are none. At least none worth investing heavily in.
The only guy who would have made sense at any level was Rex Grossman of the Bears, who at least has a Super Bowl appearance on his resume. But Grossman re-upped with the Bears for one last attempt to retain his starting job.
The Bears also re-signed Kyle Orton, leaving them with the possibility of trading away veteran Brian Griese, who briefly replaced Grossman last year before suffering a shoulder injury.
The Bears will attempt to deal Griese before next Tuesday, when he has a $300,000 roster bonus due. Chances are they won't be able to find a trading partner, though, which means Griese will be available on the open market in a few days.