One leading contender was a landfall theme to play up the battle for Gaia and its Lifestream, but that ended up feeling too ambiguous
Two-Headed Coin - The first time you flip one or more coins each turn, those coins come up heads and you win those flips
The Cyclers from Tales of Middle Earth Collectively, the Cyclers from Beyond this, Living End plays both Oliphant and Generous Ent as easy ways to cheaply fix its mana while simultaneously planting some bulky creatures in the graveyard thatll come back to haunt opponents by turn three (usually)
Read the official announcement from WotC.
As with all creature decks, once a large battlefield gets wiped, it can be hard to recover
It takes practice to consistently create great cooperative stories out of a competitive game, especially when players may have different ideas about what fun or balanced games look like