Elsha of the Infinite
The permission most creatures never touch: cast noncreature spells from a zone the rest of your deck cannot access. Two clauses stack here. The first lets you cast noncreature spells off the top of your library; the second attaches flash to exactly those top-of-library casts, so the card you'd otherwise be waiting to draw becomes a live threat you can hold up during any response window. Nothing forces those casts to instant speed: you can still fire them on your own main phase like normal spells. The flash rider is an added option, not a restriction, and that permissiveness is the point. Your library functions as a second hand you can spend whenever you like, which pushes the deckbuilder to load the top and treat the next draw as ammunition rather than a resource you're waiting on. The look-at-the-top clause keeps it from being a gamble: you always know whether the spell waiting up there is worth flashing in, and prowess converts each of those casts into a temporary combat swing. Jeskai has flirted with granting flash situationally before, but folding it into a static permission on a three-color body is a different animal. The 3/3 is almost incidental. Elsha is a rules alteration that happens to attack, and the payoff scales with how many noncreature spells the deck can afford to run, which pulls the build away from a creature-dense board and toward one engineered to keep the top card worth casting.
