Tripling the damage output of pingers and a whole host of spells is just wild
Blue has now got a reasonable selection of one drop dorks that are impressively aggressive with Delver, Cloudfin Raptor and the weaker yet passable Phantasmal Bear which together have really opened up the colour
For example, you could grab a fetch land and a Sakura-Tribe Elder off the same turn and put them back under your control very early in the game
That trend seems to have been bucked in M21, as GU has a fairly novel (and dangerous mechanic): cards that reward you for drawing cards
Card not found, on the other hand, is the basis for a deck in Modern (its namesake actually) and played in Legacy Storm decks (maybe Vintage as well, I dont know the format enough to say)
It also adds in the insurance of not allowing creatures to be regenerated, unlike Overwhelming Forces