mtg meta commander decks Magic: the Gathering or unleash Eldrazi to devour all in your path with Eldrazi Incursion Wizards of The Coast Magic:

Even if you gain control of your opponents Artifacts, reaching the 20 Artifact requirement should still be very hard

They may do something else with their turn besides kill Nissa, thinking they have another turn until shes actually a threat, but Ulvenwald Hydra typically throws a wrench into their plans

Then the recently printed Offering costs two too, also sacrifices both, and this time leaves you a Map token to either draw the top land of your library for a three for one, or give a dork a +1/+1 counter

That could easily be a 5/5 or 6/6 bonus to your Commander plus the boosts and equipment from other places for a Commander kill in one hit, or two with two attacks

The most obviously powerful one of these is Syvelun of Sea and Sky, which is basically an indestructible merfolk that draws cards and helps protect your other creatures