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.

Simic Signet

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Curiosity

Enchant creature
Whenever enchanted creature deals damage to an opponent, you may draw a card.

Mnemonic Deluge

Exile target instant or sorcery card from a graveyard. Copy that card three times. You may cast the copies without paying their mana costs. Exile Mnemonic Deluge.

Starstorm

Starstorm deals X damage to each creature.
Cycling {3} ({3}, Discard this card: Draw a card.)

Kalamax, the Stormsire

Whenever you cast your first instant spell each turn, if Kalamax, the Stormsire is tapped, copy that spell. You may choose new targets for the copy.
Whenever you copy an instant spell, put a +1/+1 counter on Kalamax.

Dualcaster Mage

Flash
When Dualcaster Mage enters, copy target instant or sorcery spell. You may choose new targets for the copy.

Xyris, the Writhing Storm

Flying
Whenever an opponent draws a card except the first one they draw in each of their draw steps, create a 1/1 green Snake creature token.
Whenever Xyris, the Writhing Storm deals combat damage to a player, you and that player each draw that many cards.

Windfall

Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.

Niv-Mizzet, Parun

This spell can't be countered.
Flying
Whenever you draw a card, Niv-Mizzet, Parun deals 1 damage to any target.
Whenever a player casts an instant or sorcery spell, you draw a card.

Goblin Electromancer

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

Guttersnipe

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

Immolating Gyre

Immolating Gyre deals X damage to each creature and planeswalker you don't control, where X is the number of instant and sorcery cards in your graveyard.

Gruul Signet

Jori En, Ruin Diver

Whenever you cast your second spell each turn, draw a card.

Rapid Hybridization

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.

Kodama's Reach

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Mana Geyser

Add {R} for each tapped land your opponents control.

Double Vision

Whenever you cast your first instant or sorcery spell each turn, copy that spell. You may choose new targets for the copy.

Swarm Intelligence

Whenever you cast an instant or sorcery spell, you may copy that spell. You may choose new targets for the copy.

Survivors' Encampment

{T}: Add {C}.
{T}, Tap an untapped creature you control: Add one mana of any color.

Glademuse

Whenever a player casts a spell, if it's not their turn, that player draws a card.

Veyran, Voice of Duality

Magecraft — Whenever you cast or copy an instant or sorcery spell, Veyran, Voice of Duality gets +1/+1 until end of turn.
If you casting or copying an instant or sorcery spell causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Gruul Turf

Gruul Turf enters tapped.
When Gruul Turf enters, return a land you control to its owner's hand.
{T}: Add {R}{G}.

Frontier Bivouac

Frontier Bivouac enters tapped.
{T}: Add {G}, {U}, or {R}.

Izzet Boilerworks

Izzet Boilerworks enters tapped.
When Izzet Boilerworks enters, return a land you control to its owner's hand.
{T}: Add {U}{R}.

Will Kenrith

+2: Until your next turn, up to two target creatures each have base power and toughness 0/3 and lose all abilities.
−2: Target player draws two cards. Until your next turn, instant, sorcery, and planeswalker spells that player casts cost {2} less to cast.
−8: Target player gets an emblem with "Whenever you cast an instant or sorcery spell, copy it. You may choose new targets for the copy."
Partner with Rowan Kenrith
Will Kenrith can be your commander.

Twinning Staff

If you would copy a spell one or more times, instead copy it that many times plus an additional time. You may choose new targets for the additional copy.
{7}, {T}: Copy target instant or sorcery spell you control. You may choose new targets for the copy.

Holdout Settlement

{T}: Add {C}. ({C} represents colorless mana.)
{T}, Tap an untapped creature you control: Add one mana of any color.

Beast Within

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.