A collective combo combo

Whenever an opponent casts a multicolored spell, you gain 4 life.

As an additional cost to cast this spell, sacrifice a creature. Target player reveals their hand and discards all cards of each of the sacrificed creature's colors.

, : You may put a multicolored creature card from your hand onto the battlefield.

Radiance — : This creature deals 1 damage to target creature and each other creature that shares a color with it.

Choose a color. Target player reveals their hand and discards all cards of that color.

, : Target player mills two cards. If two cards that share a color were milled this way, repeat this process.

When Llawan enters, return all blue creatures your opponents control to their owners' hands. Your opponents can't cast blue creature spells.

As this creature enters, choose a color. All cards that aren't on the battlefield, spells, and permanents are the chosen color in addition to their other colors.

Flying As Iona enters, choose a color. Your opponents can't cast spells of the chosen color.

As an additional cost to cast this spell, sacrifice a green creature. Search your library for a green creature card, put it onto the battlefield, then shuffle.