Branching out a bit, you can access repeatable Regenerate for your creatures via Ring of Xathrid or Medicine Bag
We'd then move to one of Magic 's most beloved planes, Innistrad, and commit harder to mechanics and specific archetypes than ever before
The Magic 2014 core set features the unstoppable Kalonian Hydra, which begins as a 4/4 but doubles in size every time it attacks
So the current Standard starts with: Wilds of Eldraine The Lost Caverns of Ixalan Murders at Karlov Manor Outlaws of Thunder Junction Bloomburrow Duskmourn: House of Horror Foundations Aetherdrift Tarkir: Dragonstorm Final Fantasy Edge of Eternities What Are Renewal Rewards
Or just something that likes to turn creatures sideways
In the same way, Id caution against taking any deal for a Black Lotus thats unreasonably undervalued, dont trust someone offering to sell you an expensive booster box for half the market price