I think most of the evergreens are evergreen for a reason. I really think flying, trample, vigilance, first strike, deathtouch, double strike, scry, haste and the new member, ward, really deserve a honorable mention at least. I think that's all of the evergreens except the horrible hexproof.
Beyond that, my vote has to go to the madness mechanic. Discarding a madness card to a looting/rummaging effect, effectively turning it into an undercosted cantrip ... that's just the best feeling you can have in a game of magic.