Half-Squirrel, Half-

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

Surgeon General Commander

Whenever you augment, enchant, or mutate a creature you control, draw a card.
{T}: Add {W}, {U}, {B}, {R}, or {G}.

Bat-

Flying
At the beginning of each end step, if an opponent lost 3 or more life this turn,
Augment {1}{B} ({1}{B}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Timmy, Power Gamer

{4}: You may put a creature card from your hand onto the battlefield.

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.

Sword of Dungeons & Dragons

Equipped creature gets +2/+2 and has protection from Rogues and from Clerics.
Whenever equipped creature deals combat damage to a player, create a 4/4 gold Dragon creature token with flying and roll a d20 (a twenty-sided die). If you roll a 20, repeat this process.
Equip {2}

Knight of the Kitchen Sink

First strike, protection from odd collector numbers (Nothing with an odd collector number can block, target, deal damage to, or attach to this creature.)

Half-Shark, Half-

At the beginning of your upkeep,
Augment {5}{U} ({5}{U}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Half-Orc, Half-

Trample
At the beginning of each end step, if an opponent was dealt damage this turn,
Augment {1}{R}{R} ({1}{R}{R}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Mer Man

When this creature enters the battlefield, you may draw a card.

Labro Bot

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

Urza, Academy Headmaster

+1: Head to AskUrza.com and click +1.
−1: Head to AskUrza.com and click -1.
−6: Head to AskUrza.com and click -6.

Serpentine

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

Booster Tutor

Open a sealed Magic booster pack, reveal the cards, and put one of them into your hand. (Remove that card from your deck before beginning a new game.)

Dirty Rat

When this creature enters the battlefield, target opponent discards a card.

Dr. Julius Jumblemorph

Dr. Julius Jumblemorph is every creature type (even if this card isn't on the battlefield).
Whenever a host enters the battlefield under your control, 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.

Bumbling Pangolin

When this creature enters the battlefield, you may destroy target artifact.

Common Iguana

When this creature enters the battlefield, you may discard a card. If you do, draw a card.

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.)

Adorable Kitten

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

Ninja

You may activate Ninja's augment ability any time you could cast an instant.
Whenever this creature deals combat damage to a player,
Augment {2}{B} ({2}{B}, Reveal this card from your hand: Combine it with target host. Augment only as—oh, never mind.)

Wild Crocodile

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