Sultai Arisen Grow Back From Beyond Ally with the Sultai to fill your graveyard and return with zombie druids with this Black-Green-Blue Commander deck
While new cards from Ikoria: Lair of Behemoths that promote keyword counters and +1+1 counters could dampen the impact of Heartless Act in future Standard environments, at the moment, this modal card kills almost everything
Playing one of these could work well, with a couple cartouches to fill combat trick slots that offer long-game value with the trial
Across seven cards, you'll find art from Supplement I: Greyhawk (1975), Players Handbook (1978), the "Red Box" Basic Rules (1983), 2nd Edition Dungeon Master's Guide (1989), 3rd Edition Monster Manual (2000), 4th Edition Dungeon Master's Guide (2008), and 5th Edition Dungeon Master's Guide (2014)
Those are some pretty hefty upgrades
If the creatures are too much to handle, it's good to use the creature destruction effect, and if the battlefield is manageable, destroying all lands is the way to go