Thunder Drake

Flying
Whenever you cast your second spell each turn, put a +1/+1 counter on Thunder Drake.

Arena Trickster

Whenever you cast your first spell during each opponent's turn, put a +1/+1 counter on Arena Trickster.

Didn't Say Please

Counter target spell. Its controller mills three cards.

Aspect of Manticore

Flash
Enchant creature
When Aspect of Manticore enters, enchanted creature gains first strike until end of turn.
Enchanted creature gets +2/+0.

Shock

Blindblast

Blindblast deals 1 damage to target creature. That creature can't block this turn.
Draw a card.

Mountain

Irreverent Revelers

When Irreverent Revelers enters, choose one —
• Destroy target artifact.
• Irreverent Revelers gains haste until end of turn.

Island

Spellgorger Weird

Whenever you cast a noncreature spell, put a +1/+1 counter on Spellgorger Weird.

Negate

Omen of the Sea

Flash
When Omen of the Sea enters, scry 2, then draw a card.
{2}{U}, Sacrifice Omen of the Sea: Scry 2.

Burning Prophet

Whenever you cast a noncreature spell, Burning Prophet gets +1/+0 until end of turn, then scry 1.

Vexing Gull

Mystic Sanctuary

({T}: Add {U}.)
Mystic Sanctuary enters tapped unless you control three or more other Islands.
When Mystic Sanctuary enters untapped, you may put target instant or sorcery card from your graveyard on top of your library.