Chamber Sentry enters the battlefield with a +1/+1 counter on it for each color of mana spent to cast it.

, TAP, Remove X +1/+1 counters from Chamber Sentry: It deals X damage to any target.

WUBRG: Return Chamber Sentry from your graveyard to your hand.

Lands you control have TAP: Add one mana of any color.

TAP: Add one mana of any color.

Lifelink

When Blood Operative enters the battlefield, you may exile target card from a graveyard.

Whenever you surveil, if Blood Operative is in your graveyard, you may pay 3 life. If you do, return Blood Operative to your hand.

Choose a creature card with converted mana cost 1 in your graveyard, then do the same for creature cards with converted mana costs 2 and 3. Return those cards to the battlefield.

Undergrowth - Search your library for a black card with converted mana cost less than or equal to the number of creature cards in your graveyard, reveal it, put it into your hand, then shuffle your library.

Whenever a nontoken creature you control dies, Midnight Reaper deals 1 damage to you and you draw a card.

Destroy all creatures with converted mana cost 3 or less.

Destroy target permanent an opponent controls. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle their library.

Assure:Put a +1/+1 counter on target creature. That creature gains indestructible until end of turn.

Assemble:
Create three 2/2 green and white Elf Knight creature tokens with vigilance.

You gain X life and draw X cards, where X is the number of creatures you control. Creatures you control get +1/+1 until end of turn.