Eternal Flame (Titan) // If you don't have, maybe sub for Humility?
With your titan fully traited you start with half mana on Eternal/Jarl. One yellow match and you can potentially start your own loop. Fill Ketras and hit Mab then hit her again with Jarl and then its clean up time..
Haven't tried it with Q.Mab because I haven't got the freeze on 4/5 gem matches trait unlocked but I assume it would work pretty well to prevent them from looping.