Hangar Scrounger

Backup 1 (When this creature enters, put a +1/+1 counter on target creature. If that's another creature, it gains the following ability until end of turn.)
Whenever this creature becomes tapped, you may discard a card. If you do, draw a card.

Spireside Infiltrator

Whenever Spireside Infiltrator becomes tapped, it deals 1 damage to each opponent.

Wildfire Awakener

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
When Wildfire Awakener enters, create X 1/1 red Elemental creature tokens with "Whenever this creature becomes tapped, it deals 1 damage to target player."

Reckless Racer

First strike
Whenever Reckless Racer becomes tapped, you may discard a card. If you do, draw a card.

Samite Herbalist

Whenever Samite Herbalist becomes tapped, you gain 1 life and scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Magda, Brazen Outlaw

Other Dwarves you control get +1/+0.
Whenever a Dwarf you control becomes tapped, create a Treasure token.
Sacrifice five Treasures: Search your library for an artifact or Dragon card, put that card onto the battlefield, then shuffle.

Augusta, Dean of Order

Other tapped creatures you control get +1/+0.
Other untapped creatures you control get +0/+1.
Whenever you attack, untap each creature you control, then tap any number of creatures you control.

Plargg, Dean of Chaos

{T}, Discard a card: Draw a card.
{4}{R}, {T}: Reveal cards from the top of your library until you reveal a nonlegendary, nonland card with mana value 3 or less. You may cast that card without paying its mana cost. Put all revealed cards not cast this way on the bottom of your library in a random order.

Plargg, Dean of Chaos // Augusta, Dean of Order

Stonybrook Schoolmaster

Whenever Stonybrook Schoolmaster becomes tapped, you may create a 1/1 blue Merfolk Wizard creature token.

Goblin Medics

Whenever Goblin Medics becomes tapped, it deals 1 damage to any target.

Renegade Wheelsmith

Whenever Renegade Wheelsmith becomes tapped, target creature can't block this turn.

Volatile Wanderglyph

Whenever Volatile Wanderglyph becomes tapped, you may discard a card. If you do, draw a card.

Scaretiller

Whenever Scaretiller becomes tapped, choose one —
• You may put a land card from your hand onto the battlefield tapped.
• Return target land card from your graveyard to the battlefield tapped.