Originating from Innistrad block, flashback is one of the most beloved Magic: The Gathering mechanics to ever see play
Coral Sword is a fair bit better, leaving behind a worthwhile permanent
For many decks, a first-turn Sergeant spells doom
Crew 1 The Lunar Whale lets you look at the top card of your library whenever you want (with one restrictionsee below), even if you don't have priority
It could be hard to fit it into an Omnath, Locus of Creation deck, for instance, but most decks with three or fewer colors should be able to find room somewhere
If this card is suspended, then when the last time counter is removed from it, both its last ability and the "cast this spell" part of the suspend ability will trigger