Octo Opus

When Octo Opus enters, create a 4/4 blue Octopus Performer creature token named Contortionist with "At the beginning of your upkeep, you may fold this token in half." (It becomes 2/2, then 1/1, ½/½, and so on.)
Sacrifice Octo Opus: Draw a card and an additional card for each of Contortionist's folds.

Coral Colony

Defender
{1}{U}, {T}: Target player mills X cards, where X is the number of creatures you control with defender. (To mill a card, a player puts the top card of their library into their graveyard.)

Mountain

Cyclone Summoner

When Cyclone Summoner enters, if you cast it from your hand, return all permanents to their owners' hands except for Giants, Wizards, and lands.

Teeterpeak Ambusher

{2}{R}: Teeterpeak Ambusher gets +2/+0 until end of turn.

Goblin Electromancer

Instant and sorcery spells you cast cost {1} less to cast.

Axgard Cavalry

{T}: Target creature gains haste until end of turn. (It can attack and {T} this turn.)

Electrolyze

Electrolyze deals 2 damage divided as you choose among one or two targets.
Draw a card.

Mind Flayer

Dominate Monster — When Mind Flayer enters, gain control of target creature for as long as you control Mind Flayer.

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Run Amok

Target attacking creature gets +3/+3 and gains trample until end of turn.

Battlewing Mystic

Kicker {R} (You may pay an additional {R} as you cast this spell.)
Flying
When Battlewing Mystic enters, if it was kicked, discard your hand, then draw two cards.

Essence Scatter

Calamity Bearer

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

Red Dragon

Flying
Fire Breath — When Red Dragon enters, it deals 4 damage to each opponent.

Meria's Outrider

Reach
Domain — When Meria's Outrider enters, it deals damage to each opponent equal to the number of basic land types among lands you control.

Field Research

Kicker {2}{U} (You may pay an additional {2}{U} as you cast this spell.)
Draw two cards. If this spell was kicked, draw three cards instead.

Coalition Warbrute

Enlist (As this creature attacks, you may tap a nonattacking creature you control without summoning sickness. When you do, add its power to this creature's until end of turn.)
Trample

Aether Channeler

When Aether Channeler enters, choose one —
• Create a 1/1 white Bird creature token with flying.
• Return another target nonland permanent to its owner's hand.
• Draw a card.

Lightning Strike

Lightning Strike deals 3 damage to any target.

Island

Shore Up

Target creature you control gets +1/+1 and gains hexproof until end of turn. Untap it. (It can't be the target of spells or abilities your opponents control.)

Guttersnipe

Whenever you cast an instant or sorcery spell, this creature deals 2 damage to each opponent.

Unlucky Witness

When Unlucky Witness dies, exile the top two cards of your library. Until your next end step, you may play one of those cards.

Archmage Emeritus

Magecraft — Whenever you cast or copy an instant or sorcery spell, draw a card.

Wormhole Serpent

{3}{U}: Target creature can't be blocked this turn.

Arni Brokenbrow

Haste
Boast — {1}: You may change Arni Brokenbrow's base power to 1 plus the greatest power among other creatures you control until end of turn. (Activate only if this creature attacked this turn and only once each turn.)

Vortex Runner

As long as you control eight or more lands, Vortex Runner gets +1/+0 and can't be blocked.

Thermo-Alchemist

Defender
{T}: Thermo-Alchemist deals 1 damage to each opponent.
Whenever you cast an instant or sorcery spell, untap Thermo-Alchemist.

Frost Trickster

Flying
When Frost Trickster enters, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Thundering Rebuke

Thundering Rebuke deals 4 damage to target creature or planeswalker.

Majestic Metamorphosis

Until end of turn, target artifact or creature becomes a 4/4 Angel artifact creature and gains flying.
Draw a card.