Hive Mind

Whenever a player casts an instant or sorcery spell, each other player copies that spell. Each of those players may choose new targets for their copy.

Grip of Chaos

Whenever a spell or ability is put onto the stack, if it has a single target, reselect its target at random. (Select from among all legal targets.)

Fireball

This spell costs {1} more to cast for each target beyond the first.
Fireball deals X damage divided evenly, rounded down, among any number of targets.

Lightning Strike

Lightning Strike deals 3 damage to any target.

Possibility Storm

Whenever a player casts a spell from their hand, that player exiles it, then exiles cards from the top of their library until they exile a card that shares a card type with it. That player may cast that card without paying its mana cost. Then they put all cards exiled with this enchantment on the bottom of their library in a random order.

Forest

Ball Lightning

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Haste (This creature can attack and {T} as soon as it comes under your control.)
At the beginning of the end step, sacrifice this creature.

Splintering Wind

{2}{G}: This enchantment deals 1 damage to target creature. Create a 1/1 green Splinter creature token. It has flying and "Cumulative upkeep {G}." When it leaves the battlefield, it deals 1 damage to you and each creature you control. (At the beginning of its controller's upkeep, that player puts an age counter on it, then sacrifices it unless they pay its upkeep cost for each age counter on it.)

Burnout

Counter target instant spell if it's blue.
Draw a card at the beginning of the next turn's upkeep.

Counterspell

Mountain

Book Burning

Any player may have Book Burning deal 6 damage to them. If no one does, target player mills six cards.

Goblin Game

Each player hides at least one item, then all players reveal them simultaneously. Each player loses life equal to the number of items they revealed. The player who revealed the fewest items then loses half their life, rounded up. If two or more players are tied for fewest, each loses half their life, rounded up.

Eye of the Storm

Whenever a player casts an instant or sorcery card, exile it. Then that player copies each instant or sorcery card exiled with this enchantment. For each copy, the player may cast the copy without paying its mana cost.

Anarchist

When this creature enters, you may return target sorcery card from your graveyard to your hand.