Every year during the All Star break Dave Cameron from Fangraphs releases his annual trade value list. The basic concept is which players would bring the most return if they were made available by their current club. # 1 is pretty obvious as he has been there pretty much since he debuted.
It is hard to argue most of the choices since you can pretty much interchange the honorable mentions with numbers 35-50.
Here are the honorable mentions.
Here is a link to the overview which will guide you to each write up. One thing that you will take away is that Mike Trout is good at baseball.