Mercurial Spelldancer

Mercurial Spelldancer can't be blocked.
Whenever you cast a noncreature spell, put an oil counter on Mercurial Spelldancer.
Whenever Mercurial Spelldancer deals combat damage to a player, you may remove two oil counters from it. If you do, when you next cast an instant or sorcery spell this turn, copy that spell. You may choose new targets for the copy.

Become Immense

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Target creature gets +6/+6 until end of turn.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Gruul Signet

Frontier Bivouac

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

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.

Simic Signet

Solemn Simulacrum

When this creature enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When this creature dies, you may draw a card.

Cultivate

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.

Prey Upon

Target creature you control fights target creature you don't control. (Each deals damage equal to its power to the other.)

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Izzet Signet

Island

Forest

Giant Growth

Target creature gets +3/+3 until end of turn.

Command Tower

Kodama's Reach

Mountain

Ancient Animus

Put a +1/+1 counter on target creature you control if it's legendary. Then it fights target creature an opponent controls. (Each deals damage equal to its power to the other.)