Tarnation Vista

Tarnation Vista enters tapped. As it enters, choose a color.
{T}: Add one mana of the chosen color.
{1}, {T}: For each color among monocolored permanents you control, add one mana of that color.

Agate Instigator

Offspring {1}{R} (You may pay an additional {1}{R} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
Whenever another creature you control enters, this creature deals 1 damage to each opponent.

Mountain

Kediss, Emberclaw Familiar

Whenever a commander you control deals combat damage to an opponent, it deals that much damage to each other opponent.
Partner (You can have two commanders if both have partner.)

Unclaimed Territory

As Unclaimed Territory enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type.

Swamp

Blazing Rootwalla

{R}: Blazing Rootwalla gets +2/+0 until end of turn. Activate only once each turn.
Madness {0} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Gamble

Search your library for a card, put that card into your hand, discard a card at random, then shuffle.

Impact Tremors

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Treasure

{T}, Sacrifice this artifact: Add one mana of any color.

Mercenary

{T}: Target creature you control gets +1/+0 until end of turn. Activate only as a sorcery.

Kindred Charge

Choose a creature type. For each creature you control of the chosen type, create a token that's a copy of that creature. Those tokens gain haste. Exile them at the beginning of the next end step.

Cindering Cutthroat

Cindering Cutthroat enters with a +1/+1 counter on it if an opponent lost life this turn.
{1}{B/R}: Cindering Cutthroat gains menace until end of turn. (It can't be blocked except by two or more creatures.)

Secluded Courtyard

As this land enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type or activate an ability of a creature source of the chosen type.

The Nipton Lottery

Choose a creature at random. You gain control of that creature until end of turn. Untap it. It gains haste until end of turn. Then destroy all other creatures.

Dragonskull Summit

Dragonskull Summit enters tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

Riveteers Requisitioner

When Riveteers Requisitioner dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Blitz {2}{R} (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.)

Gev, Scaled Scorch

Ward—Pay 2 life.
Other creatures you control enter with an additional +1/+1 counter on them for each opponent who lost life this turn.
Whenever you cast a Lizard spell, Gev, Scaled Scorch deals 1 damage to target opponent.

Hired Claw

Whenever you attack with one or more Lizards, Hired Claw deals 1 damage to target opponent.
{1}{R}: Put a +1/+1 counter on Hired Claw. Activate only if an opponent lost life this turn and only once each turn.

Maskwood Nexus

Creatures you control are every creature type. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
{3}, {T}: Create a 2/2 blue Shapeshifter creature token with changeling. (It is every creature type.)

Viashino Sandscout

Haste (This creature can attack and {T} as soon as it comes under your control.)
At the beginning of the end step, return Viashino Sandscout to its owner's hand. (Return it only if it's on the battlefield.)

Hellspur Posse Boss

Other outlaws you control have haste. (Assassins, Mercenaries, Pirates, Rogues, and Warlocks are outlaws.)
When Hellspur Posse Boss enters, create two 1/1 red Mercenary creature tokens with "{T}: Target creature you control gets +1/+0 until end of turn. Activate only as a sorcery."

Basilisk Collar

Equipped creature has deathtouch and lifelink. (Any amount of damage it deals to a creature is enough to destroy it. Damage dealt by this creature also causes you to gain that much life.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Viashino Heretic

{1}{R}, {T}: Destroy target artifact. Viashino Heretic deals damage to that artifact's controller equal to the artifact's mana value.

Mindclaw Shaman

When Mindclaw Shaman enters, target opponent reveals their hand. You may cast an instant or sorcery spell from among those cards without paying its mana cost.

Valley Flamecaller

If a Lizard, Mouse, Otter, or Raccoon you control would deal damage to a permanent or player, it deals that much damage plus 1 instead.

Panharmonicon

If an artifact or creature entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Sol Ring

Dagger Caster

When Dagger Caster enters, it deals 1 damage to each opponent and 1 damage to each creature your opponents control.

Command Tower

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

Gratuitous Violence

If a creature you control would deal damage to a permanent or player, it deals double that damage instead.

Obstinate Familiar

If you would draw a card, you may skip that draw instead.

Cover of Darkness

As Cover of Darkness enters, choose a creature type.
Creatures of the chosen type have fear. (They can't be blocked except by artifact creatures and/or black creatures.)

Arcane Signet

Iridescent Vinelasher

Offspring {2} (You may pay an additional {2} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
Landfall — Whenever a land you control enters, this creature deals 1 damage to target opponent.

Viashino Sandsprinter

Trample, haste
At the beginning of the end step, return Viashino Sandsprinter to its owner's hand. (Return it only if it's on the battlefield.)
Cycling {R} ({R}, Discard this card: Draw a card.)

Path of Ancestry

Path of Ancestry enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Landfall — Whenever a land you control enters, this creature deals 1 damage to target opponent.
(This token's mana cost is {B}.)

Unexpected Windfall

As an additional cost to cast this spell, discard a card.
Draw two cards and create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

War Room

{T}: Add {C}.
{3}, {T}, Pay life equal to the number of colors in your commanders' color identity: Draw a card.

Whenever another creature you control enters, this creature deals 1 damage to each opponent.
(This token's mana cost is {1}{R}.)

Viashino Lashclaw

{T}, Discard a card: Creatures you control gain haste until end of turn.

Mezzio Mugger

Whenever Mezzio Mugger attacks, exile the top card of each player's library. You may play those cards this turn, and you may spend mana as though it were mana of any color to cast those spells.
Blitz {2}{R} (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.)

Taurean Mauler

Changeling (This card is every creature type.)
Whenever an opponent casts a spell, you may put a +1/+1 counter on this creature.

Kolaghan's Command

Choose two —
• Return target creature card from your graveyard to your hand.
• Target player discards a card.
• Destroy target artifact.
• Kolaghan's Command deals 2 damage to any target.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Viashino Sandstalker

Haste (This creature can attack and {T} as soon as it comes under your control.)
At the beginning of the end step, return Viashino Sandstalker to its owner's hand. (Return it only if it's on the battlefield.)

Immolation Shaman

Whenever an opponent activates an ability of an artifact, creature, or land that isn't a mana ability, Immolation Shaman deals 1 damage to that player.
{3}{R}{R}: Immolation Shaman gets +3/+3 and gains menace until end of turn.

Hearthborn Battler

Haste
Whenever a player casts their second spell each turn, Hearthborn Battler deals 2 damage to target opponent.

Shared Animosity

Whenever a creature you control attacks, it gets +1/+0 until end of turn for each other attacking creature that shares a creature type with it.

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.