Citanul Stalwart

Rainbow fixing on a one-drop body usually has to be paid for somewhere: artifacts bury the flexibility in a mana rock, and creatures that tap for any color tend to arrive later or bigger. This puts the whole spectrum on a 1/1 by borrowing the effort from a second permanent. The ability costs both its own tap and the tap of an untapped artifact or creature you control, so one activation spends two permanents' turns to yield a single mana of any color. The in the cost caps it hard: no matter how wide the board, this produces exactly one mana per turn cycle, never a stream. What it does is turn idle taps into fixing and, in the same motion, into extra mana. That mana is real acceleration; a color your lands alone could not have produced now sits in your pool, the same structural trick that Springleaf Drum pulls by tapping a body and itself for a color. The catch is the ceiling. Where a mana dork produces on its own every turn, this needs a spare permanent to turn sideways each time and gives back only one mana for the two taps it consumes. It reads best as a splash-enabler that happens to nudge your curve: it paints a single problematic pip whatever color you need, and if that pip is the one keeping you a mana short, it has quietly ramped you there.