Explosive Prodigy

Vivid — When this creature enters, it deals X damage to target creature an opponent controls, where X is the number of colors among permanents you control.

Shimmerwilds Growth

Enchant land
As this Aura enters, choose a color.
Enchanted land is the chosen color.
Whenever enchanted land is tapped for mana, its controller adds an additional one mana of the chosen color.

Mountain

Forest

Dragonbroods' Relic

{T}, Tap an untapped creature you control: Add one mana of any color.
{3}{W}{U}{B}{R}{G}, Sacrifice this artifact: Create a 4/4 Dragon creature token named Reliquary Dragon that's all colors. It has flying, lifelink, and "When this token enters, it deals 3 damage to any target." Activate only as a sorcery.

Feisty Spikeling

Changeling (This card is every creature type.)
During your turn, this creature has first strike.

Sanar, Innovative First-Year

Vivid — At the beginning of your first main phase, reveal cards from the top of your library until you reveal X nonland cards, where X is the number of colors among permanents you control. For each of those colors, you may exile a card of that color from among the revealed cards. Then shuffle. You may cast the exiled cards this turn.

Temur Tawnyback

When this creature enters, draw a card, then discard a card.

Stormkeld Prowler

Whenever you cast a spell with mana value 5 or greater, put two +1/+1 counters on this creature.

Savage Mansion

This land enters tapped.
{T}: Add {R} or {G}.
{4}, {T}: Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Island

Gurmag Nightwatch

When this creature enters, look at the top three cards of your library. You may put one of those cards back on top of your library. Put the rest into your graveyard.

Wildvine Pummeler

Vivid — This spell costs {1} less to cast for each color among permanents you control.
Reach, trample