There are a number of cards I think have potential, but a lot is going to depend on rotation, potential bans, and how powerful the upcoming three Standard sets of this year will be.
It cannot attack this turn
SythisSythis, SramSram and MazzyMazzy, if only to quote a few, never scoff at more card draw
Combo 3: Dragon Ravine + A-Assault Core + C-Crush Wyvern Activate Dragon Ravine , discard C-Crush Wyvern , send Destrudo the Lost Dragons Frisson from deck to graveyard
Thassas Oracle doesnt even need to be in play when its trigger resolves in order for you to win, and should someone Stifle your first attempt, youre still in the game to try again
Double-Sided Printing Full front artwork with a matching card back, so every card looks complete from both sides