Steve Young has to be one, he was a tremendous athlete.
Luke Staley would have been one had his knee not been torn up.
Ziggy Ansah might be at the top in terms of his freak athletic abilities
Taysom Hill joines the list in my opinion
Itula Mili is one that I would put on there as well
There are others (Ronnie Jenkins could fly) and especially many lineman that were freaky for their position, but I like my list.