It's very strong in decks that can reliably have the extra mana on the back side, such as Mono-Black Control with its Cabal Coffers
Cayth, Famed Mechanist The secondary commander for the Creative Energy precon, Cayth, Famed Mechanist is kind of busted
With Kardur, Doomscourge be patient enough to let your opponents play down some heavy hitters then you get maximum impact from the ETB that goads all opposing creatures
Only Ancestral Recall is firmly in the broken bucket with color requirements, because not only is it just that absurd, it is that absurd at any point in the game, whereas topdecking a Mox Sapphire on turn twelve is usually the same as topdecking an Island
In fact, some cards that look like bombs can be complete duds in a format, maybe because they're too expensive or require you to build a deck in a way that's not really feasible
It turns a potentially awkward multi-color draw into a smooth, color-fixed hand, earning its reputation as the essential lubricant for the games most mechanical and crunchy strategies