Shattered Seraph

The clever part lives in the hand, before this ever hits the battlefield. For two mana you can pitch it from your hand to grant any land a new tap ability that produces white, blue, or black, and that land keeps the ability until you finally cast the Seraph out of exile. This is fixing, not acceleration: your land count and mana total do not change, but a land that could only make one color now covers all three you need, smoothing out the color-hungry turns that a seven-drop across three colors would otherwise choke on. The loop is honest because of the timing lock. The land only produces its three colors "until this card is cast from exile," so the moment you deploy the 4/4 flier and gain the three life, the fixing switches off. You trade the color-smoothing for the body, never keeping both. It answers an old friction in high-color-count decks, where the expensive gold cards you want to end games with are also the hardest to cast on curve; here the finisher fixes its own colors from the sidelines and then steps onto the field. The exile-cast clause also sidesteps the usual cost of pitch-for-fixing effects, that you have spent your payoff for good, since the card is only parked in exile, not discarded. A color-fixer that graduates into a threat, structured so it never holds both jobs at once.