Humming-

Flying
Whenever you attack with two or more creatures,
Augment {3}{W} ({3}{W}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Druid of the Sacred Beaker

{T}: Add {G} for each Crossbreed Labs watermark among permanents you control.

Gnome-Made Engine

When this creature enters, create a 1/1 colorless Gnome artifact creature token.

Half-Squirrel, Half-

Whenever a nontoken creature enters,
Augment {G} ({G}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Serpentine

Landfall — Whenever a land you control enters,
Augment {2}{G} ({2}{G}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Half-Kitten, Half-

Whenever you're dealt damage,
Augment {2}{W} ({2}{W}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Voracious Vacuum

When this creature enters, put a +1/+1 counter on target creature.

Wild Crocodile

When this creature enters, search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Shellephant

{0}: Choose one. You may activate this ability while Shellephant is in any zone.
• Shellephant has base power and toughness 1/4.
• Shellephant has base power and toughness 3/3.

Dr. Julius Jumblemorph

Dr. Julius Jumblemorph is every creature type (even if this card isn't on the battlefield).
Whenever a host you control enters, you may search your library and/or graveyard for a card with augment and combine it with that host. If you search your library this way, shuffle.

Shaggy Camel

When this creature enters, creatures you control get +1/+1 until end of turn.

Steam-Powered

{5}:
Augment {4} ({4}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Labro Bot

When this creature enters, return target host card or card with augment from your graveyard to your hand.

Plains

Angelic Rocket

Flying
When this creature enters, you may destroy target nonland permanent.

Rhino-

Whenever this creature blocks,
Augment {3}{W} ({3}{W}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Slaying Mantis

Just a second (As long as this spell is on the stack, players can't move permanents.)
Slaying Mantis enters by being thrown from a distance of at least three feet.
When Slaying Mantis enters, it fights each creature an opponent controls that it touched as it entered.

Eager Beaver

When this creature enters, you may untap target permanent.

Teacher's Pet

{2}{W}, Sacrifice Teacher's Pet: Search your library for a card with augment, combine it with target host you control, then shuffle.

Success!

Target creature gets +2/+2 until end of turn. If it's a host or has augment, it gains lifelink until end of turn.

Really Epic Punch

Target creature you control gets +2/+2 if it's a host or has augment. Then it fights target creature you don't control.

Hydradoodle

As Hydradoodle enters, roll X six-sided dice. Hydradoodle enters with a number of +1/+1 counters on it equal to the total of those results.
Reach, trample

Squirrel Dealer

When Squirrel Dealer enters, ask a person outside the game "Do you like Squirrels?" If they do, create a 1/1 green Squirrel creature token.

Mother Kangaroo

When this creature enters, roll a six-sided die. Put a number of +1/+1 counters on this creature equal to the result.

Monkey-

Whenever a nontoken creature you control dies,
Augment {2}{G} ({2}{G}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Better Than One

A person outside the game becomes your teammate. (Choose any number of cards in your hand, on top of your library, or on the battlefield under your control. Those cards become your teammate's hand, library, and permanents, respectively.)

Adorable Kitten

When this creature enters, roll a six-sided die. You gain life equal to the result.

Willing Test Subject

Reach
Whenever you roll a 4 or higher on a die, put a +1/+1 counter on Willing Test Subject.
{6}: Roll a six-sided die.

Forest

Ordinary Pony

When this creature enters, you may exile target non-Horse creature you control that wasn't put onto the battlefield with this ability this turn, then return it to the battlefield under its owner's control.

Clever Combo

Search your library for a host card or a card with augment, reveal it, put it into your hand, then shuffle.