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.

Spectral Sailor

Flash (You may cast this spell any time you could cast an instant.)
Flying
{3}{U}: Draw a card.

Sleeper Dart

When this artifact enters, draw a card.
{T}, Sacrifice this artifact: Target creature doesn't untap during its controller's next untap step.

Knight of the Ebon Legion

{2}{B}: This creature gets +3/+3 and gains deathtouch until end of turn.
At the beginning of your end step, if a player lost 4 or more life this turn, put a +1/+1 counter on this creature. (Damage causes loss of life.)

Golden Egg

When this artifact enters, draw a card.
{1}, {T}, Sacrifice this artifact: Add one mana of any color.
{2}, {T}, Sacrifice this artifact: You gain 3 life.

Heroes' Bane

This creature enters with four +1/+1 counters on it.
{2}{G}{G}: Put X +1/+1 counters on this creature, where X is its power.

Innkeeper's Talent

(Gain the next level as a sorcery to add its ability.)
At the beginning of combat on your turn, put a +1/+1 counter on target creature you control.
{G}: Level 2
Permanents you control with counters on them have ward {1}.
{3}{G}: Level 3
If you would put one or more counters on a permanent or player, put twice that many of each of those kinds of counters on that permanent or player instead.

Go for the Throat

Training Grounds

Activated abilities of creatures you control cost {2} less to activate. This effect can't reduce the mana in that cost to less than one mana.

Jace, Unraveler of Secrets

+1: Scry 1, then draw a card.
−2: Return target creature to its owner's hand.
−8: You get an emblem with "Whenever an opponent casts their first spell each turn, counter that spell."

Tough Cookie

When this creature enters, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")
{2}{G}: Until end of turn, target noncreature artifact you control becomes a 4/4 artifact creature.
{2}, {T}, Sacrifice this creature: You gain 3 life.

Garruk, Cursed Huntsman

0: Create two 2/2 black and green Wolf creature tokens with "When this token dies, put a loyalty counter on each Garruk you control."
−3: Destroy target creature. Draw a card.
−6: You get an emblem with "Creatures you control get +3/+3 and have trample."