User blog comment:Krufix/A Scientific Discussion of Trollbuilds. Episode 1/@comment-5894384-20130225163633

Well, there's AP Warwick. Of course, AP WW has been discovered quite a while ago and never really set fuse to anything, especially since it's only useful for the heavy sustain + damage that comes with it.

AP Leona can be another build. She has somewhat poor AP ratios (like Nami or Thresh), but, in my opinion, she stands out more because she has some incredibly funny pushing capabilities.It's easy to clear waves with W+E. You can also deal Tons of Damage to turrets if you have Lichbane (Q's AP scalings + Lichbane proc + Autoattack, all of which benefit from AP), which can prove very useful during pushes.

Other than that and builds mentioned before, I really cannot come up with more. There are many champions that have AP scalings that won't do any good (Like Wukong having a mindblowing 60%AP scaling on his clone damage, as if anyone takes damage from it to begin with).