Bolas's Citadel Combos
Gravebane Zombie + Bolas's Citadel + Panharmonicon
Bolas's Citadel + Mortuary + Ugin's Conjurant
Bolas's Citadel + Mortuary + Walking Ballista
Bolas's Citadel + Sensei's Divining Top + Aetherflux Reservoir
Children of Korlis + Mortuary + Bolas's Citadel
Doomsday + Commander's Sphere + Bolas's Citadel
Doomsday + Thassa's Oracle + Bolas's Citadel
Golem's Heart + Bolas's Citadel + Sensei's Divining Top
Golgari Thug + Bolas's Citadel + Healer of the Pride
Golgari Thug + Dross Harvester + Bolas's Citadel
Gravebane Zombie + Bolas's Citadel + Elesh Norn, Mother of Machines
Bolas's Citadel + Mortuary + Stonecoil Serpent
Leonin Elder + Bolas's Citadel + Sensei's Divining Top
Lotus Petal + Bolas's Citadel + Arcbound Reclaimer
Mortuary + Bolas's Citadel + Carrion Feeder
Mortuary + Bolas's Citadel + Gray Merchant of Asphodel
Mortuary + Bolas's Citadel + Viscera Seer
Queza, Augur of Agonies + Sensei's Divining Top + Bolas's Citadel
Rograkh, Son of Rohgahh + Bolas's Citadel + Mortuary
Combo result
Infinite colorless mana. Infinite ETB. Infinite LTB. Infinite death triggers. Infinite sacrifice triggers. Infinite storm count.
Prerequisites
Rograkh in hand, in the command zone or on top of your library. All other permanents on the battlefield. You have enough mana to pay for commander tax if Rograkh is your commander.