Prismabasher

Trample
Vivid — When this creature enters, up to X target creatures you control get +X/+X until end of turn, where X is the number of colors among permanents you control.

Shinestriker

Flying
Vivid — When this creature enters, draw cards equal to the number of colors among permanents you control.

Tam, Mindful First-Year

Each other creature you control has hexproof from each of its colors.
{T}: Target creature you control becomes all colors until end of turn.

Aurora Awakener

Trample
Vivid — When this creature enters, reveal cards from the top of your library until you reveal X permanent cards, where X is the number of colors among permanents you control. Put any number of those permanent cards onto the battlefield, then put the rest of the revealed cards on the bottom of your library in a random order.

Elemental Spectacle

Vivid — Create a number of 5/5 red and green Elemental creature tokens equal to the number of colors among permanents you control. Then you gain life equal to the number of creatures you control.

Vivid Revival

Return up to three target multicolored cards from your graveyard to your hand. Exile Vivid Revival.

Bloom Tender

Vivid — {T}: For each color among permanents you control, add one mana of that color.

Dragonfire Blade

Equipped creature gets +2/+2 and has hexproof from monocolored.
Equip {4}. This ability costs {1} less to activate for each color of the creature it targets.

Luminollusk

Deathtouch
Vivid — When this creature enters, you gain life equal to the number of colors among permanents you control.

Rime Chill

Vivid — This spell costs {1} less to cast for each color among permanents you control.
Tap up to two target creatures. Put a stun counter on each of them. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Draw a card.

Glister Bairn

Vivid — At the beginning of combat on your turn, another target creature you control gets +X/+X until end of turn, where X is the number of colors among permanents you control.

Prismatic Undercurrents

Vivid — When this enchantment enters, search your library for up to X basic land cards, where X is the number of colors among permanents you control. Reveal those cards, put them into your hand, then shuffle.
You may play an additional land on each of your turns.

Chromatic Orrery

You may spend mana as though it were mana of any color.
{T}: Add {C}{C}{C}{C}{C}.
{5}, {T}: Draw a card for each color among permanents you control.