Windfall

Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.

The Ruinous Powers

At the beginning of your upkeep, choose an opponent at random. Exile the top card of that player's library. Until end of turn, you may play that card and you may spend mana as though it were mana of any color to cast it. When you cast a spell this way, its owner loses life equal to its mana value.

Chef's Kiss

Gain control of target spell that targets only a single permanent or player. Copy it, then reselect the targets at random for the spell and the copy. The new targets can't be you or a permanent you control.

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 Possibility Storm on the bottom of their library in a random order.

Gríma, Saruman's Footman

Gríma, Saruman's Footman can't be blocked.
Whenever Gríma deals combat damage to a player, that player exiles cards from the top of their library until they exile an instant or sorcery card. You may cast that card without paying its mana cost. Then that player puts the exiled cards that weren't cast this way on the bottom of their library in a random order.

Disrupt Decorum

Goad all creatures you don't control. (Until your next turn, those creatures attack each combat if able and attack a player other than you if able.)

Counterspell

Tibalt's Trickery

Counter target spell. Choose 1, 2, or 3 at random. Its controller mills that many cards, then exiles cards from the top of their library until they exile a nonland card with a different name than that spell. They may cast that card without paying its mana cost. Then they put the exiled cards on the bottom of their library in a random order.

Ludevic, Necro-Alchemist

At the beginning of each player's end step, that player may draw a card if a player other than you lost life this turn.
Partner (You can have two commanders if both have partner.)

Last One Standing

Choose a creature at random, then destroy the rest.

Plargg and Nassari

At the beginning of your upkeep, each player exiles cards from the top of their library until they exile a nonland card. An opponent chooses a nonland card exiled this way. You may cast up to two spells from among the other cards exiled this way without paying their mana costs.

Vial Smasher the Fierce

Whenever you cast your first spell each turn, choose an opponent at random. Vial Smasher the Fierce deals damage equal to that spell's mana value to that player or a planeswalker that player controls.
Partner (You can have two commanders if both have partner.)

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.)

Kaervek the Merciless

Whenever an opponent casts a spell, Kaervek the Merciless deals damage equal to that spell's mana value to any target.

Chaos Mutation

Exile any number of target creatures controlled by different players. For each creature exiled this way, its controller reveals cards from the top of their library until they reveal a creature card, puts that card onto the battlefield, then puts the rest on the bottom of their library in a random order.

Nightscape Familiar

Blue spells and red spells you cast cost {1} less to cast.
{1}{B}: Regenerate Nightscape Familiar.

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Wild Magic Surge

Destroy target permanent an opponent controls. Its controller reveals cards from the top of their library until they reveal a permanent card that shares a card type with that permanent. They put that card onto the battlefield and the rest on the bottom of their library in a random order.

Relic of Sauron

{T}: Add two mana in any combination of {U}, {B}, and/or {R}.
{3}, {T}: Draw two cards, then discard a card.

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Wild Evocation

At the beginning of each player's upkeep, that player reveals a card at random from their hand. If it's a land card, the player puts it onto the battlefield. Otherwise, the player casts it without paying its mana cost if able.

Perplexing Chimera

Whenever an opponent casts a spell, you may exchange control of Perplexing Chimera and that spell. If you do, you may choose new targets for the spell. (If the spell becomes a permanent, you control that permanent.)