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.

Thousand-Year Elixir

You may activate abilities of creatures you control as though those creatures had haste.
{1}, {T}: Untap target creature.

Wirewood Symbiote

Return an Elf you control to its owner's hand: Untap target creature. Activate only once each turn.

Evolution Witness

{1}{G}: Adapt 2. (If this creature has no +1/+1 counters on it, put two +1/+1 counters on it.)
Whenever one or more +1/+1 counters are put on this creature, return target permanent card from your graveyard to your hand.

Dionus, Elvish Archdruid

Elves you control have "Whenever this creature becomes tapped during your turn, untap it and put a +1/+1 counter on it. This ability triggers only once each turn."

Three Tree City

As Three Tree City enters, choose a creature type.
{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to the number of creatures you control of the chosen type.

Insidious Roots

Creature tokens you control have "{T}: Add one mana of any color."
Whenever one or more creature cards leave your graveyard, create a 0/1 green Plant creature token, then put a +1/+1 counter on each Plant you control.

Circle of Dreams Druid

{T}: Add {G} for each creature you control.

Llanowar Elves

Reclamation Sage

When this creature enters, you may destroy target artifact or enchantment.

Incubation Druid

{T}: Add one mana of any type that a land you control could produce. If this creature has a +1/+1 counter on it, add three mana of that type instead.
{3}{G}{G}: Adapt 3. (If this creature has no +1/+1 counters on it, put three +1/+1 counters on it.)

Priest of Titania

{T}: Add {G} for each Elf on the battlefield.

Temur Sabertooth

{1}{G}: You may return another creature you control to its owner's hand. If you do, this creature gains indestructible until end of turn.

Fyndhorn Elves

Champions of the Perfect

As an additional cost to cast this spell, behold an Elf and exile it. (Exile an Elf you control or an Elf card from your hand.)
Whenever you cast a creature spell, draw a card.
When this creature leaves the battlefield, return the exiled card to its owner's hand.

Elvish Harbinger

When this creature enters, you may search your library for an Elf card, reveal it, then shuffle and put that card on top.
{T}: Add one mana of any color.

Beast Whisperer

Whenever you cast a creature spell, draw a card.

Chronicle of Victory

As Chronicle of Victory enters, choose a creature type.
Creatures you control of the chosen type get +2/+2 and have first strike and trample.
Whenever you cast a spell of the chosen type, draw a card.

Rishkar, Peema Renegade

When Rishkar enters, put a +1/+1 counter on each of up to two target creatures.
Each creature you control with a counter on it has "{T}: Add {G}."

Elvish Mystic

Formidable Speaker

When this creature enters, you may discard a card. If you do, search your library for a creature card, reveal it, put it into your hand, then shuffle.
{1}, {T}: Untap another target permanent.