Elementalist Adept

Flash (You may cast this spell any time you could cast an instant.)
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Ghitu Lavarunner

As long as there are two or more instant and/or sorcery cards in your graveyard, this creature gets +1/+0 and has haste. (It can attack and {T} as soon as it comes under your control.)

Sure Strike

Target creature gets +3/+0 and gains first strike until end of turn. (It deals combat damage before creatures without first strike.)

Think Twice

Draw a card.
Flashback {2}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Elusive Spellfist

Whenever you cast a noncreature spell, this creature gets +1/+0 until end of turn and can't be blocked this turn.

Goblin Surprise

Choose one —
• Creatures you control get +2/+0 until end of turn.
• Create two 1/1 red Goblin creature tokens.

Refute

Counter target spell. Draw a card, then discard a card.

Mountain

Red Mage's Rapier

Job select (When this Equipment enters, create a 1/1 colorless Hero creature token, then attach this to it.)
Equipped creature has "Whenever you cast a noncreature spell, this creature gets +2/+0 until end of turn" and is a Wizard in addition to its other types.
Equip {3}

Run Away Together

Choose two target creatures controlled by different players. Return those creatures to their owners' hands.

Summon: G.F. Ifrit

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after IV.)
I, II — You may discard a card. If you do, draw a card.
III, IV — Add {R}.

Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Draw a card.

Involuntary Employment

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. Create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Witness Protection

Enchant creature
Enchanted creature loses all abilities and is a green and white Citizen creature with base power and toughness 1/1 named Legitimate Businessperson. (It loses all other colors, card types, creature types, and names.)

Island

Mocking Sprite

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

Haste Magic

Target creature gets +3/+1 and gains haste until end of turn. Exile the top card of your library. You may play it until your next end step.

Jeskai Sage

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When this creature dies, draw a card.