Hoarding Ogre

Whenever Hoarding Ogre attacks, roll a d20.
1—9 | Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
10—19 | Create two Treasure tokens.
20 | Create three Treasure tokens.

Etali, Primal Storm

Whenever Etali attacks, exile the top card of each player's library, then you may cast any number of spells from among those cards without paying their mana costs.

Tenth District Guard

When Tenth District Guard enters, target creature gets +0/+1 until end of turn.

Audacious Thief

Whenever Audacious Thief attacks, you draw a card and you lose 1 life.

Trusted Pegasus

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever Trusted Pegasus attacks, target attacking creature without flying gains flying until end of turn.

Armory of Iroas

Whenever equipped creature attacks, put a +1/+1 counter on it.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Burning-Tree Vandal

Riot (This creature enters with your choice of a +1/+1 counter or haste.)
Whenever Burning-Tree Vandal attacks, you may discard a card. If you do, draw a card.

Infectious Horror

Whenever Infectious Horror attacks, each opponent loses 2 life.

Isshin, Two Heavens as One

If a creature attacking causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.