It offers incredible land recursion for multicolored decks with fetch lands and can help mill the top of your library after a Brainstorm
It means that having it in your opening hand is unlikely to be a good thing, but it does a lot of work after the first couple of turns, so its usually worth plopping one into your decklist
Be aware that these cards are in no discernible order other than the whim of my trivia questions
Aftermath Analyst is a half-step behind the truly best-in-class ETB creatures in terms of cards milled, but its still cheap to cast and has the many advantages of creature cards: attacking, blocking, ease of recursion, and so on
It can also transform for the low cost of a single red mana, assuming you play three or more instants or sorceries that turn
Phantom Premonition has quite a lot of great general EDH reprints, from Ghostly Prison to Windfall