The pool of such commanders is deep, with great options in every color combination: consider Sai, Master Thopterist, Darien, King of Kjeldor, The Mycotyrant, Prossh, Skyraider of Kher, and Akim, the Soaring Wind
The nice part is you dont even have to attack with this creature to gain the quest counters
Angelic Sell-Sword Claim Jumper Cloud, Ex-SOLDIER Cloud, Midgar Mercenary Cloud, Planet's Champion Freestrider Aces Generous Betty Wray Jedit Ojanen, Mercenary Mercenaries Mercenary Informer Omenport Vigilante Robaran Mercenaries Silver Sable, Mercenary Leader Squall, Gunblade Duelist Squall, SeeD Mercenary Sterling Keykeeper Taii Wakeen, Perfect Shot Wild Pack Squad
Of course, you can enchant your creatures if you want to boost them
Another solution is simply to play Destructive Flow in a deck full of cheap cards and kill your opponent with one- and two-drops while no one can cast anything bigger