Mono-Red Cavalcade, for example, is a deck thats relatively popular on the Arena ladder but that only had one representative in the entire tournament
Yshtola, Nights Blessed Y'shtola, Night's Blessed has an incredible ceiling on its card advantage
Any one, tow or three drop that is near the top of what it does remains in the cube and sees plenty of play even when better cards are printed however the top end just stop seeing play all together.
Then, when Keruga enters the battlefield, draw a card for each other permanent you control with a mana value of three or greater, which will be all of them
It's not a card you want to play on turn 3, but come turn 5-6, it has the ability to be a game changer, whether you're flashing back an important early game spell, or using the Harmonize ability to cast an expensive spell at a reduced rate