Arena

{3}, {T}: Tap target creature you control and target creature of an opponent's choice they control. Those creatures fight each other. (Each deals damage equal to its power to the other.)

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Chevill, Bane of Monsters

Deathtouch
At the beginning of your upkeep, if your opponents control no permanents with bounty counters on them, put a bounty counter on target creature or planeswalker an opponent controls.
Whenever a permanent an opponent controls with a bounty counter on it dies, you gain 3 life and draw a card.

Generous Patron

When Generous Patron enters the battlefield, support 2. (Put a +1/+1 counter on each of up to two other target creatures.)
Whenever you put one or more counters on a creature you don't control, draw a card.

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Tenacious Underdog

Blitz—{2}{B}{B}, Pay 2 life. (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)
You may cast Tenacious Underdog from your graveyard using its blitz ability.

Ruthless Predation

Target creature you control gets +1/+2 until end of turn. It fights target creature you don't control. (Each deals damage equal to its power to the other.)

Fight Rigging

Hideaway 5 (When this enchantment enters the battlefield, look at the top five cards of your library, exile one face down, then put the rest on the bottom in a random order.)
At the beginning of combat on your turn, put a +1/+1 counter on target creature you control. Then if you control a creature with power 7 or greater, you may play the exiled card without paying its mana cost.

Fynn, the Fangbearer

Deathtouch
Whenever a creature you control with deathtouch deals combat damage to a player, that player gets two poison counters. (A player with ten or more poison counters loses the game.)

Back for More

Return target creature card from your graveyard to the battlefield. When you do, it fights up to one target creature you don't control. (Each deals damage equal to its power to the other.)

Warbriar Blessing

Enchant creature you control
When Warbriar Blessing enters the battlefield, enchanted creature fights up to one target creature you don't control. (Each deals damage equal to its power to the other.)
Enchanted creature gets +0/+2.

Setessan Tactics

Strive — This spell costs {G} more to cast for each target beyond the first.
Until end of turn, any number of target creatures each get +1/+1 and gain "{T}: This creature fights another target creature."

Arcane Signet

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Golgari Rot Farm

Golgari Rot Farm enters the battlefield tapped.
When Golgari Rot Farm enters the battlefield, return a land you control to its owner's hand.
{T}: Add {B}{G}.

Three Visits

Search your library for a Forest card, put it onto the battlefield, then shuffle.

Barroom Brawl

Target creature you control fights target creature the opponent to your left controls. Then that player may copy this spell and may choose new targets for the copy.

Ezuri's Predation

For each creature your opponents control, create a 4/4 green Phyrexian Beast creature token. Each of those tokens fights a different one of those creatures.

Swamp

Tail Swipe

Choose target creature you control and target creature you don't control. If you cast this spell during your main phase, the creature you control gets +1/+1 until end of turn. Then those creatures fight each other. (Each deals damage equal to its power to the other.)

Black Market

Whenever a creature dies, put a charge counter on Black Market.
At the beginning of your precombat main phase, add {B} for each charge counter on Black Market.

Black Market Connections

At the beginning of your precombat main phase, choose one or more —
• Sell Contraband — Create a Treasure token. You lose 1 life.
• Buy Information — Draw a card. You lose 2 life.
• Hire a Mercenary — Create a 3/2 colorless Shapeshifter creature token with changeling. You lose 3 life. (It has every creature type.)

Termination Facilitator

{T}: Put a bounty counter on target creature or planeswalker. Activate only as a sorcery.
Whenever a creature or planeswalker an opponent controls with a bounty counter on it is dealt damage, destroy it.

Bootleggers' Stash

Lands you control have "{T}: Create a Treasure token."

Sign in Blood

Target player draws two cards and loses 2 life.

Forest

Deathreap Ritual

Morbid — At the beginning of each end step, if a creature died this turn, you may draw a card.

Boxing Ring

Whenever a creature enters the battlefield under your control, it fights up to one target creature you don't control with the same mana value.
{T}: Create a Treasure token. Activate only if you control a creature that fought this turn.

Duel for Dominance

Coven — Choose target creature you control and target creature you don't control. If you control three or more creatures with different powers, put a +1/+1 counter on the chosen creature you control. Then the chosen creatures fight each other. (They each deal damage equal to their power to the other.)

Saryth, the Viper's Fang

Other tapped creatures you control have deathtouch.
Other untapped creatures you control have hexproof.
{1}, {T}: Untap another target creature or land you control.

Phyrexian Arena

At the beginning of your upkeep, you draw a card and you lose 1 life.

Revel in Riches

Whenever a creature an opponent controls dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
At the beginning of your upkeep, if you control ten or more Treasures, you win the game.

Overgrown Tomb

({T}: Add {B} or {G}.)
As Overgrown Tomb enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

Golgari Guildgate

Golgari Guildgate enters the battlefield tapped.
{T}: Add {B} or {G}.

Night's Whisper

Outmuscle

Put a +1/+1 counter on target creature you control, then it fights target creature you don't control. (Each deals damage equal to its power to the other.)
Adamant — If at least three green mana was spent to cast this spell, the creature you control gains indestructible until end of turn.

Read the Bones

Scry 2, then draw two cards. You lose 2 life.

Nature's Lore

Search your library for a Forest card, put that card onto the battlefield, then shuffle.