Though this Azorius Spirit Soldier demands a price of seven mana, its mana cost is reduced by one mana for each Spirit you control, meaning it can reliably be cast for two mana
If that creature would leave the battlefield, exile it instead of putting it anywhere else
The Creative team said they weren't staffed to create two planes in a single year (something we're equipped to handle now), so they suggested a story where something happened that was so impactful that it would allow for the complete shift in Zendikar's mechanics
Doomraider Encampment Plane: Ushval Whenever a creature enters the battlefield, it gains Haste and Trample until end of turn
Modern Horizons 2 is one of the few sets to give them any significant focus, including the card Squirrel Sovereign
Reparations Once again we have an elegant card that gets the most you could possibly get out of five mana in terms of damage-based removal short of an even bigger drawback