Redcap Heelslasher

Backup 1 (When this creature enters, put a +1/+1 counter on target creature. If that's another creature, it gains the following ability until end of turn.)
First strike

Tetsuko Umezawa, Fugitive

Creatures you control with power or toughness 1 or less can't be blocked.

Forest

Trailblazing Historian

Haste
{T}: Another target creature gains haste until end of turn.

War Historian

Reach
War Historian has indestructible as long as it attacked a battle this turn.

Zephyr Singer

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Flying, vigilance
When Zephyr Singer enters, put a flying counter on each creature that convoked it.

Kyren Flamewright

{2}{R}, {T}, Discard a card: Create two 1/1 blue and red Elemental creature tokens. Creatures you control get +1/+0 and gain haste until end of turn.

Invasion of Mercadia

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When Invasion of Mercadia enters, you may discard a card. If you do, draw two cards.

Invasion of Mercadia // Kyren Flamewright

Atraxa's Fall

Destroy target artifact, battle, enchantment, or creature with flying.

Mountain

Ragavan, Nimble Pilferer

Whenever Ragavan, Nimble Pilferer deals combat damage to a player, create a Treasure token and exile the top card of that player's library. Until end of turn, you may cast that card.
Dash {1}{R} (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)

Mutagen Connoisseur

Flying, vigilance
Mutagen Connoisseur gets +1/+0 for each transformed permanent you control.

Baral and Kari Zev

First strike, menace
Whenever you cast your first instant or sorcery spell each turn, you may cast a spell with lesser mana value that shares a card type with it from your hand without paying its mana cost. If you don't, create First Mate Ragavan, a legendary 2/1 red Monkey Pirate creature token. It gains haste until end of turn.

Ephara's Dispersal

This spell costs {2} less to cast if it targets an attacking creature.
Return target creature to its owner's hand. Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Truga Cliffcharger

Trample
When Truga Cliffcharger enters, you may discard a card. If you do, search your library for a land or battle card, reveal it, put it into your hand, then shuffle.

Invasion of Ergamon

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When Invasion of Ergamon enters, create a Treasure token. Then you may discard a card. If you do, draw a card.

Invasion of Ergamon // Truga Cliffcharger

Serpent-Blade Assailant

Backup 1 (When this creature enters, put a +1/+1 counter on target creature. If that's another creature, it gains the following ability until end of turn.)
Deathtouch

Zhalfirin Shapecraft

Target creature has base power and toughness 4/3 until end of turn.
Draw a card.

Kogla and Yidaro

When Kogla and Yidaro enters, choose one —
• It gains trample and haste until end of turn.
• It fights target creature you don't control.
{2}{R}{G}, Discard Kogla and Yidaro: Destroy up to one target artifact or enchantment. Shuffle Kogla and Yidaro into your library from your graveyard, then draw a card.

Chomping Kavu

Backup 1 (When this creature enters, put a +1/+1 counter on target creature. If that's another creature, it gains the following ability until end of turn.)
This creature can't be blocked by creatures with power 2 or less.

Island

Wicked Slumber

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Tap up to two target creatures. Put a stun counter on either of them. Then put a stun counter on either of them. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Ral's Reinforcements

Create two 1/1 blue and red Elemental creature tokens.

Negate

Preening Champion

Flying
When Preening Champion enters, create a 1/1 blue and red Elemental creature token.

Volcanic Spite

Volcanic Spite deals 3 damage to target creature, planeswalker, or battle. You may put a card from your hand on the bottom of your library. If you do, draw a card.