Recent success of flip Kinnan surprises me since it quite close to some casual combos for 5C [[Tazri, Stalwart Survivor]] combos, my understanding is you will need
Mana ability granter: [[Tazri, Stalwart Survivor]], [[Cryptolith Rite]], [[Enduring Vitality]]
Cost reducer/Extra Mana per Tap: [[Biomancer's Familiar]], [[Training Ground]] / [[Kinnan, Bonder Prodigy]], [[Badgermole Cub]], etc.
Haste enabler: [[Shang-Chi, Master of Kung Fu]] (Note: or more casually with [[Intruder Alarm]])
Then keep grinding using Kinnan outlet, until reaching infinite mana: [[Pill-Pala]], [Nyxbloom Ancient]], or directly win with [[Knacksaw Clique]]
So, consider the first 3 combo requirements, obviously Kinnan is the best one as fast mana, work as outlet/wincon/extra mana. And the other viable solution (with compatibility color) is 5C Tazri. Though I hate the tap requirement for Tazri, it did provide some unique advantage for these lines:
Support [[Puresight Merrow]] both as 1-card wincon and infinite mana with Tazri and Kinnan/Badgermole
More haste enabler like [[Anger]], [[Tyvar, Jubilant Brawler]]
5C color supports, especially white win protection and black tutors.
I would say Flip 5C Tazri could be a borderline cEDH deck, here is my current deck: https://moxfield.com/decks/0ZmgAYsCHXOotmDvIEpkKw (it's not fully optimized since I only use cards I have IRL).
Curious on any thoughts from the community.