Burrowing

Enchant creature
Enchanted creature has mountainwalk. (It can't be blocked as long as defending player controls a Mountain.)

Quarum Trench Gnomes

{T}: If target Plains is tapped for mana, it produces colorless mana instead of white mana. (This effect lasts indefinitely.)

Orcish Librarian

{R}, {T}: Look at the top eight cards of your library. Exile four of them at random, then put the rest on top of your library in any order.

Raging River

Whenever one or more creatures you control attack, each defending player divides all creatures without flying they control into a "left" pile and a "right" pile. Then, for each attacking creature you control, choose "left" or "right." That creature can't be blocked this combat except by creatures with flying and creatures in a pile with the chosen label.

Ruby Leech

First strike
Red spells you cast cost {R} more to cast.

Spinal Villain

Mannichi, the Fevered Dream

{1}{R}: Switch each creature's power and toughness until end of turn.

Fickle Efreet

Whenever Fickle Efreet attacks or blocks, flip a coin at end of combat. If you lose the flip, an opponent gains control of Fickle Efreet.

Brand of Ill Omen

Enchant creature
Cumulative upkeep {R} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Enchanted creature's controller can't cast creature spells.

Telim'Tor's Edict

Exile target permanent you own or control.
Draw a card at the beginning of the next turn's upkeep.

Total War

Whenever a player attacks with one or more creatures, destroy all untapped non-Wall creatures that player controls that didn't attack, except for creatures the player hasn't controlled continuously since the beginning of the turn.

Hidetsugu's Second Rite

If target player has exactly 10 life, Hidetsugu's Second Rite deals 10 damage to that player.

Ali Baba

Dong Zhou, the Tyrant

When Dong Zhou, the Tyrant enters, target creature an opponent controls deals damage equal to its power to that player.

Dwarven Armory

{2}, Sacrifice a land: Put a +2/+2 counter on target creature. Activate only during any upkeep step.

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.

Impatience

At the beginning of each player's end step, if that player didn't cast a spell this turn, Impatience deals 2 damage to that player.

Mijae Djinn

Whenever Mijae Djinn attacks, flip a coin. If you lose the flip, remove Mijae Djinn from combat and tap it.

Disharmony

Cast this spell only during combat before blockers are declared.
Untap target attacking creature and remove it from combat. Gain control of that creature until end of turn.

Mindblaze

Choose a nonland card name and a number greater than 0. Target player reveals their library. If that library contains exactly the chosen number of cards with the chosen name, Mindblaze deals 8 damage to that player. Then that player shuffles.

Bomb Squad

{T}: Put a fuse counter on target creature.
At the beginning of your upkeep, put a fuse counter on each creature with a fuse counter on it.
Whenever a creature has four or more fuse counters on it, remove all fuse counters from it and destroy it. That creature deals 4 damage to its controller.

Parallectric Feedback

Parallectric Feedback deals damage to target spell's controller equal to that spell's mana value.

Kookus

Trample
At the beginning of your upkeep, if you don't control a creature named Keeper of Kookus, Kookus deals 3 damage to you and attacks this turn if able.
{R}: Kookus gets +1/+0 until end of turn.

Chaos Harlequin

{R}: Exile the top card of your library. If that card is a land card, Chaos Harlequin gets -4/-0 until end of turn. Otherwise, Chaos Harlequin gets +2/+0 until end of turn.

Mudhole

Target player exiles all land cards from their graveyard.

Tide of War

Whenever one or more creatures block, flip a coin. If you win the flip, each blocking creature is sacrificed by its controller. If you lose the flip, each blocked creature is sacrificed by its controller.

Starke of Rath

{T}: Destroy target artifact or creature. That permanent's controller gains control of Starke of Rath. (This effect lasts indefinitely.)

Backdraft

Choose a player who cast one or more sorcery spells this turn. Backdraft deals damage to that player equal to half the damage dealt by one of those sorcery spells this turn, rounded down.

Dwarven Song

One or more target creatures become red until end of turn.

Risky Move

At the beginning of each player's upkeep, that player gains control of Risky Move.
When you gain control of Risky Move from another player, choose a creature you control and an opponent. Flip a coin. If you lose the flip, that opponent gains control of that creature.

Chaos Moon

At the beginning of each upkeep, count the number of permanents. If the number is odd, until end of turn, red creatures get +1/+1 and whenever a player taps a Mountain for mana, that player adds an additional {R}. If the number is even, until end of turn, red creatures get -1/-1 and if a player taps a Mountain for mana, that Mountain produces colorless mana instead of any other type.

Collapsing Borders

Domain — At the beginning of each player's upkeep, that player gains 1 life for each basic land type among lands they control. Then Collapsing Borders deals 3 damage to that player.

Widespread Panic

Whenever a spell or ability causes its controller to shuffle their library, that player puts a card from their hand on top of their library.

Crag Saurian

Whenever a source deals damage to Crag Saurian, that source's controller gains control of Crag Saurian.

Chaoslace

Target spell or permanent becomes red. (Its mana symbols remain unchanged.)

Ydwen Efreet

Whenever Ydwen Efreet blocks, flip a coin. If you lose the flip, remove Ydwen Efreet from combat and it can't block this turn. Creatures it was blocking that had become blocked by only Ydwen Efreet this combat become unblocked.

Electryte

Whenever Electryte deals combat damage to defending player, it deals damage equal to its power to each blocking creature.

No Quarter

Whenever a creature becomes blocked by a creature with lesser power, destroy the blocking creature.
Whenever a creature blocks a creature with lesser power, destroy the attacking creature.

Fighting Chance

For each blocking creature, flip a coin. If you win the flip, prevent all combat damage that would be dealt by that creature this turn.

Mages' Contest

You and target spell's controller bid life. You start the bidding with a bid of 1. In turn order, each player may top the high bid. The bidding ends if the high bid stands. The high bidder loses life equal to the high bid. If you win the bidding, counter that spell.

Crevasse

Creatures with mountainwalk can be blocked as though they didn't have mountainwalk.