Arni Metalbrow

Whenever a creature you control attacks or a creature you control enters attacking, you may pay {1}{R}. If you do, you may put a creature card with mana value less than that creature's mana value from your hand onto the battlefield tapped and attacking.

Bogardan Hellkite

Flash
Flying
When this creature enters, it deals 5 damage divided as you choose among any number of targets.

Ifrit, Warden of Inferno

(As this Saga enters and after your draw step, add a lore counter.)
I — Lunge — Ifrit fights up to one other target creature.
II, III — Brimstone — Add {R}{R}{R}{R}. If Ifrit has three or more lore counters on it, exile it, then return it to the battlefield (front face up).

Clive, Ifrit's Dominant

When Clive enters, you may discard your hand, then draw cards equal to your devotion to red. (Each {R} in the mana costs of permanents you control counts toward your devotion to red.)
{4}{R}{R}, {T}: Exile Clive, then return it to the battlefield transformed under its owner's control. Activate only as a sorcery.

Clive, Ifrit's Dominant // Ifrit, Warden of Inferno

Defiant Ogre

When this creature enters, choose one —
• Put a +1/+1 counter on this creature.
• Destroy target artifact.

Brazen Freebooter

When this creature enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Canoptek Spyder

Flying
Fabricator Claw Array — Whenever another nontoken artifact creature or Vehicle you control enters, draw a card.

Chaos Maw

When this creature enters, it deals 3 damage to each other creature.

Chancellor of the Forge

You may reveal this card from your opening hand. If you do, at the beginning of the first upkeep, create a 1/1 red Phyrexian Goblin creature token with haste.
When this creature enters, create X 1/1 red Phyrexian Goblin creature tokens with haste, where X is the number of creatures you control.

Demanding Dragon

Flying
When this creature enters, it deals 5 damage to target opponent unless that player sacrifices a creature of their choice.

Goblin Commando

When this creature enters, it deals 2 damage to target creature.

Devilish Valet

Trample, haste
Alliance — Whenever another creature you control enters, double this creature's power until end of turn.

Cragganwick Cremator

When this creature enters, discard a card at random. If you discard a creature card this way, this creature deals damage equal to that card's power to target player or planeswalker.

Faultgrinder

Trample
When this creature enters, destroy target land.
Evoke {4}{R} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Combustible Gearhulk

First strike
When this creature enters, target opponent may have you draw three cards. If the player doesn't, you mill three cards, then this creature deals damage to that player equal to the total mana value of those cards.

Crater Hellion

Echo {4}{R}{R} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When this creature enters, it deals 4 damage to each other creature.

Firbolg Flutist

Enthralling Performance — When this creature enters, gain control of target creature you don't control until end of turn. Untap it. It gains haste and myriad until end of turn. (Whenever it attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)

Conquering Manticore

Flying
When this creature enters, gain control of target creature an opponent controls until end of turn. Untap that creature. It gains haste until end of turn.

Clone Shell

Imprint — When this creature enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom of your library in any order.
When this creature dies, turn the exiled card face up. If it's a creature card, put it onto the battlefield under your control.

Dragon Trainer

When this creature enters, create a 4/4 red Dragon creature token with flying.

Avalanche Riders

Haste
Echo {3}{R} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When this creature enters, destroy target land.

Bone Pit Brute

Menace (This creature can't be blocked except by two or more creatures.)
When this creature enters, target creature gets +4/+0 until end of turn.

Canoptek Scarab Swarm

Flying
Feeder Mandibles — When this creature enters, exile target player's graveyard. For each artifact or land card exiled this way, create a 1/1 colorless Insect artifact creature token with flying.

Emrakul's Hatcher

When this creature enters, create three 0/1 colorless Eldrazi Spawn creature tokens. They have "Sacrifice this token: Add {C}."

Flametongue Kavu

When this creature enters, it deals 4 damage to target creature.

Coal Stoker

When this creature enters, if you cast it from your hand, add {R}{R}{R}.

Chimney Rabble

Haste
When this creature enters, create a 1/1 red Phyrexian Goblin creature token.

Cavalier of Flame

{1}{R}: Creatures you control get +1/+0 and gain haste until end of turn.
When this creature enters, discard any number of cards, then draw that many cards.
When this creature dies, it deals X damage to each opponent and each planeswalker they control, where X is the number of land cards in your graveyard.

Firemaw Kavu

Echo {5}{R} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When this creature enters, it deals 2 damage to target creature.
When this creature leaves the battlefield, it deals 4 damage to target creature.

Bogardan Rager

Flash (You may cast this spell any time you could cast an instant.)
When this creature enters, target creature gets +4/+0 until end of turn.

Automatic Librarian

When this creature enters, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Fervent Cathar

Haste
When this creature enters, target creature can't block this turn.

Bronze Walrus

When this creature enters, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)
{T}: Add one mana of any color.

Crossway Vampire

When this creature enters, target creature can't block this turn.

Glarewielder

Haste
When this creature enters, up to two target creatures can't block this turn.
Evoke {1}{R} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Jaxis, the Troublemaker

{R}, {T}, Discard a card: Create a token that's a copy of another target creature you control. It gains haste and "When this token dies, draw a card." Sacrifice it at the beginning of the next end step. Activate only as a sorcery.
Blitz {1}{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.)

Caldera Hellion

Devour 1 (As this creature enters, you may sacrifice any number of creatures. It enters with that many +1/+1 counters on it.)
When this creature enters, it deals 3 damage to each creature.