Lee Sin + Xin Zhao

Ultimate - Kicks a player then gets knocked back even more due to the outstanding power (able to get kicked off the map) if the enemy is hit/challenged.

Nunu + Tf
Ultimate - while casting Absolute Zero, can move anywhere on map

Ahri + Brand ult

Ultimate - You dart around able to use the ult 3 times, aditionaly if you are near an enemy champion while you use this ability a fireball will go out and hit and enemy champion bounceing to everything untill targets are out of range.

Nunu + Kennen

Ultimate: Slows and stuns enemies and dmges the more u channel and u can moves while in it

Ziggs + Xerath

Throws 3 powerful, arcane-infused bombs, dealing massive damage in a wide area.

Heimerdinger and karma: Nothing happens

Kat and Garen. Throws blades into the sky that deal massive ammounts of scaling magic damage and even more the less HP the champ has. This with kat's passive.

Skarner and Twisted Fate

Impale target to drag, teleport back to base fountain.

Udyr and Karma, just think about it

Edit: originally just joking, but actually thinking about it: Uddie passively does aoe damage and has a bonus cone aoe on his 3rd hit. Active, 2 charges, makes Uddie's next ability have an additional affect:
Tiger- dot spreads to up to 3 random nearby enemies (prioritizes champions) and deals 30% more damage
Turtle- shield affects nearby allied champions, and is 30% stronger
Bear- short dash towards the cursor (flash distance), and speed boost is 30% faster

Wow.... I now really want to see udyr like this, with the ult scaling like jayces does (effective at level 1, but still gets levelled like an ult)