Harmonic Prodigy is high on our list for one big reason: it works incredibly well with Burning-Tree Emissary, and Burning-Tree Emissary is already a staple of the Historic format
Unfortunately, we havent heard a peep out of You Make the Card since
But forcing someone to choose between keeping Counterspell mana open (or other responses) or playing a creature on their turn, it a hard decision to make
It is pretty hard to have this out perform a Careful Study, it may technically cost a mana less but not being active for two whole turns after Careful Study is playable greatly slows down the utility of Frantic Search
How about a combat trigger that gives haste and doubles your targets power
Afterwards, the card goes into exile, and you can cast Brazen Borrower, which is a 3/1 creature with flash and flying that can only block creatures with flying