Impending Disaster

At the beginning of your upkeep, if there are seven or more lands on the battlefield, sacrifice Impending Disaster and destroy all lands.

Mountain

The Underworld Cookbook

{T}, Discard a card: Create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")
{4}, {T}, Sacrifice The Underworld Cookbook: Return target creature card from your graveyard to your hand.

Warp World

Each player shuffles all permanents they own into their library, then reveals that many cards from the top of their library. Each player puts all artifact, creature, and land cards revealed this way onto the battlefield, then does the same for enchantment cards, then puts all cards revealed this way that weren't put onto the battlefield on the bottom of their library.

Magus of the Wheel

{1}{R}, {T}, Sacrifice Magus of the Wheel: Each player discards their hand, then draws seven cards.

Scrambleverse

For each nonland permanent, choose a player at random. Then each player gains control of each permanent for which they were chosen. Untap those permanents.

Elturel Survivors

Trample, myriad (Whenever this creature attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
As long as Elturel Survivors is attacking, it gets +X/+0, where X is the number of lands defending player controls.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Anger of the Gods

Anger of the Gods deals 3 damage to each creature. If a creature dealt damage this way would die this turn, exile it instead.

Mirror of Life Trapping

Whenever a creature enters, if it was cast, exile it, then return all other permanent cards exiled with Mirror of Life Trapping to the battlefield under their owners' control.

Asmoranomardicadaistinaculdacar

As long as you've discarded a card this turn, you may pay {B/R} to cast this spell.
When Asmoranomardicadaistinaculdacar enters, you may search your library for a card named The Underworld Cookbook, reveal it, put it into your hand, then shuffle.
Sacrifice two Foods: Target creature deals 6 damage to itself.