Core Set 2021

Seasoned Hallowblade | Creature | Human Warrior | Discard a card: Tap Seasoned Hallowblade. It gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.) | Manuel Castañón

Tempered Veteran | Creature | Human Knight | {W}, {T}: Put a +1/+1 counter on target creature with a +1/+1 counter on it. {4}{W}{W}, {T}: Put a +1/+1 counter on target creature. | Izzy

Jeskai Elder | Creature | Human Monk | Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.) Whenever Jeskai Elder deals combat damage to a player, you may draw a card. If you do, discard a card. | Craig J Spearing

Kitesail Freebooter | Creature | Human Pirate | Flying When Kitesail Freebooter enters the battlefield, target opponent reveals their hand. You choose a noncreature, nonland card from it. Exile that card until Kitesail Freebooter leaves the battlefield. | Dan Scott

Tavern Swindler | Creature | Human Rogue | {T}, Pay 3 life: Flip a coin. If you win the flip, you gain 6 life. | Cynthia Sheppard

Chandra's Pyreling | Creature | Elemental Lizard | Whenever a source you control deals noncombat damage to an opponent, Chandra's Pyreling gets +1/+0 and gains double strike until end of turn. (It deals both first-strike and regular combat damage.) | Josu Hernaiz

Heartfire Immolator | Creature | Human Wizard | Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.) {R}, Sacrifice Heartfire Immolator: It deals damage equal to its power to target creature or planeswalker. | Donato Giancola

Quirion Dryad | Creature | Dryad | Whenever you cast a spell that's white, blue, black, or red, put a +1/+1 counter on Quirion Dryad. | Todd Lockwood

Watcher of the Spheres | Creature | Bird Wizard | Flying Creature spells with flying you cast cost {1} less to cast. Whenever another creature with flying enters the battlefield under your control, Watcher of the Spheres gets +1/+1 until end of turn. | G-host Lee

Alpine Houndmaster | Creature | Human Warrior | When Alpine Houndmaster enters the battlefield, you may search your library for a card named Alpine Watchdog and/or a card named Igneous Cur, reveal them, put them into your hand, then shuffle. Whenever Alpine Houndmaster attacks, it gets +X/+0 until end of turn, where X is the number of other attacking creatures. | Mark Behm

Conclave Mentor | Creature | Centaur Cleric | If one or more +1/+1 counters would be put on a creature you control, that many plus one +1/+1 counters are put on that creature instead. When Conclave Mentor dies, you gain life equal to its power. | Raoul Vitale