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.

Omni-Changeling

Changeling (This card is every creature type.)
Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
You may have this creature enter as a copy of any creature on the battlefield, except it has changeling.

Mirrorform

Each nonland permanent you control becomes a copy of target non-Aura permanent.

Morophon, the Boundless

Changeling (This card is every creature type.)
As Morophon enters, choose a creature type.
Spells of the chosen type you cast cost {W}{U}{B}{R}{G} less to cast. This effect reduces only the amount of colored mana you pay.
Other creatures you control of the chosen type get +1/+1.

Oko, Shadowmoor Scion

At the beginning of your first main phase, you may pay {U}. If you do, transform Oko.
−1: Mill three cards. You may put a permanent card from among them into your hand.
−3: Create two 3/3 green Elk creature tokens.
−6: Choose a creature type. You get an emblem with "Creatures you control of the chosen type get +3/+3 and have vigilance and hexproof."

Oko, Lorwyn Liege

At the beginning of your first main phase, you may pay {G}. If you do, transform Oko.
+2: Up to one target creature gains all creature types. (This effect doesn't end.)
+1: Target creature gets -2/-0 until your next turn.

Oko, Lorwyn Liege // Oko, Shadowmoor Scion

Harmonized Crescendo

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Choose a creature type. Draw a card for each permanent you control of that type.