emerge cards mtg Unscathed (FR) You gain 3 life. MTGNexus - Emerge From Rot

You have no maximum hand size and dont lose the game for having 0 or less life

If you aren't able to do so because Knowledge Vault left the battlefield or changed controllers before the ability resolves, nothing happens

And finally, in conjunction with Mycosynth Lattice, Karn can deny your opponent all activated abilities for the rest of the game, including mana production

This will matter a lot in cEDH but is also huge in more casual Commander

As for the X spells themselves, that includes a rich variety of Hydras such as Hydroid Krasis, which is overwhelmingly strong even without Zaxara there to generate additional value on the side, along with other staple Hydras like Lifeblood Hydra, Protean Hydra, and the mighty Genesis Hydra