Sapphire Medallion

Blue spells you cast cost {1} less to cast.

Visions of Beyond

Draw a card. If a graveyard has twenty or more cards in it, draw three cards instead.

Emerald Medallion

Green spells you cast cost {1} less to cast.

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.

Ruin Crab

Landfall — Whenever a land you control enters, each opponent mills three cards. (To mill a card, a player puts the top card of their library into their graveyard.)

Snapcaster Mage

Flash
When Snapcaster Mage enters, target instant or sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost. (You may cast that card from your graveyard for its flashback cost. Then exile it.)

Growth Spiral

Draw a card. You may put a land card from your hand onto the battlefield.

Ragavan, Nimble Pilferer

Whenever Ragavan, Nimble Pilferer deals combat damage to a player, create a Treasure token and exile the top card of that player's library. Until end of turn, you may cast that card.
Dash {1}{R} (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)

Fork

Copy target instant or sorcery spell, except that the copy is red. You may choose new targets for the copy.

Wilderness Reclamation

At the beginning of your end step, untap all lands you control.

Planar Gate

Creature spells you cast cost {2} less to cast.

Slime Against Humanity

Create a 0/0 green Ooze creature token with trample. Put X +1/+1 counters on it, where X is two plus the total number of cards you own in exile and in your graveyard that are Oozes or are named Slime Against Humanity.
A deck can have any number of cards named Slime Against Humanity.

Storm Seeker

Storm Seeker deals damage to target player equal to the number of cards in that player's hand.

Ruby Medallion

Red spells you cast cost {1} less to cast.

Mana Matrix

Instant and enchantment spells you cast cost {2} less to cast.

Hedron Crab

Landfall — Whenever a land you control enters, target player mills three cards.

Iceberg Cancrix

Whenever another snow permanent you control enters, you may have target player mill two cards.

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.