Jozu: 7/10 Captain Ability: 2X ATK & 2X HP to QCK units. Special: Nullify damage from DEX enemies for 1 turn. HP: 3300. ATK: 987. RCV: 231. Jozu has a very powerful special, but when he's captaining a QCK Team, he probably shouldn't be facing off against too many DEX enemies.
Boa Hancock: 10/10 Captain Ability: 2.75X ATK to QCK and PSY while HP is above 70%. Special: Delay enemies by 1 turn and heal. HP: 2860. ATK: 1320. RCV: 515. Boa Hancock provides an incredible boost and an incredible special and incredible stats. She's an incredible QCK captain, as she should for being a 6* unit.
Ace: 7.5/10 Captain Ability: 2.5X ATK to QCK units. Special: 15X QCK damage to all enemies. HP: 2886. ATK: 1020. RCV: 279. He's simply a QCK boosting captain with really no other good benefits, but 2.5X captains are still powerful.
Top 10 units for a QCK Team (in no particular order).