Bloomburrow

Brambleguard Captain | Creature | Mouse Soldier | At the beginning of combat on your turn, target creature you control gets +X/+0 until end of turn, where X is Brambleguard Captain's power. | Quintin Gleim

Brazen Collector | Creature | Raccoon Rogue | First strike Whenever Brazen Collector attacks, add {R}. Until end of turn, you don't lose this mana as steps and phases end. | Aldo Domínguez

Coruscation Mage | Creature | Otter Wizard | 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.) Whenever you cast a noncreature spell, this creature deals 1 damage to each opponent. | Gaboleps

Flamecache Gecko | Creature | Lizard Warlock | When Flamecache Gecko enters, if an opponent lost life this turn, add {B}{R}. {1}{R}, Discard a card: Draw a card. | Brian Valeza

Harnesser of Storms | Creature | Otter Wizard | Whenever you cast a noncreature or Otter spell, you may exile the top card of your library. Until end of turn, you may play that card. This ability triggers only once each turn. | Bram Sels

Heartfire Hero | Creature | Mouse Soldier | Valiant — Whenever Heartfire Hero becomes the target of a spell or ability you control for the first time each turn, put a +1/+1 counter on it. When Heartfire Hero dies, it deals damage equal to its power to each opponent. | Jakub Kasper

Quaketusk Boar | Creature | Elemental Boar | Reach, trample, haste | Andrew Mar

Reptilian Recruiter | Creature | Lizard Warrior | Trample When Reptilian Recruiter enters, choose target creature. If that creature's power is 2 or less or if you control another Lizard, gain control of that creature until end of turn, untap it, and it gains haste until end of turn. | Joshua Cairos

Teapot Slinger | Creature | Raccoon Warrior | Menace Whenever you expend 4, Teapot Slinger deals 2 damage to each opponent. (You expend 4 as you spend your fourth total mana to cast spells during a turn.) | Wisnu Tan

Seedglaive Mentor | Creature | Mouse Soldier | Vigilance, haste Valiant — Whenever Seedglaive Mentor becomes the target of a spell or ability you control for the first time each turn, put a +1/+1 counter on it. | Vincent Christiaens

Stormcatch Mentor | Creature | Otter Wizard | Haste Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.) Instant and sorcery spells you cast cost {1} less to cast. | Manuel Castañón

Fireglass Mentor | Creature | Lizard Warlock | At the beginning of your second main phase, if an opponent lost life this turn, exile the top two cards of your library. Choose one of them. Until end of turn, you may play that card. | Henry Peters

Wandertale Mentor | Creature | Raccoon Bard | Whenever you expend 4, put a +1/+1 counter on Wandertale Mentor. (You expend 4 as you spend your fourth total mana to cast spells during a turn.) {T}: Add {R} or {G}. | Jakub Kasper