This goes for the prices cards may have in future, so its a tricky one
Myr Battlesphere - Another popular ramp finisher, this is a great one to flicker because it not only swarms, but can use that swarm by attacking with itself for big damage and then get flickered again after the ability resolves before dying to a lethal block
Sapphire has two key cards that act as payoffs for your extra ink: Belle, Strange but Special and Hades, Infernal Schemer
Not only can you re-cast this card should it die, but Savvy Trader will reduce the cost of everything that you cast from your graveyard
This is the MDFC that I think could legitimately go in any deck
However, we have chosen the 15 best Adventures in the Forgotten Realms cards that will most likely influence the historic format in a big way without the need to be banned, and only one of them has the dice rolling element