Agatha's Soul Cauldron

You may spend mana as though it were mana of any color to activate abilities of creatures you control.
Creatures you control with +1/+1 counters on them have all activated abilities of all creature cards exiled with Agatha's Soul Cauldron.
{T}: Exile target card from a graveyard. When a creature card is exiled this way, put a +1/+1 counter on target creature you control.

Alchemist's Assistant

Lifelink
Renew — {1}{B}, Exile this card from your graveyard: Put a lifelink counter on target creature. Activate only as a sorcery.

Banishing Light

When this enchantment enters, exile target nonland permanent an opponent controls until this enchantment leaves the battlefield.

Ketramose, the New Dawn

Menace, lifelink, indestructible
Ketramose can't attack or block unless there are seven or more cards in exile.
Whenever one or more cards are put into exile from graveyards and/or the battlefield during your turn, you draw a card and lose 1 life.