Glorybringer | Creature | Dragon | Flying, haste
You may exert Glorybringer as it attacks. When you do, it deals 4 damage to target non-Dragon creature an opponent controls. (An exerted creature won't untap during your next untap step.) | Sam Burley
Manticore of the Gauntlet | Creature | Manticore | When Manticore of the Gauntlet enters the battlefield, put a -1/-1 counter on target creature you control. Manticore of the Gauntlet deals 3 damage to target opponent or planeswalker. | James Paick
Trueheart Twins | Creature | Jackal Warrior | You may exert Trueheart Twins as it attacks. (It won't untap during your next untap step.)
Whenever you exert a creature, creatures you control get +1/+0 until end of turn. | Matt Stewart
Samut, Voice of Dissent | Legendary Creature | Human Warrior | Flash
Double strike, vigilance, haste
Other creatures you control have haste.
{W}, {T}: Untap another target creature. | Aleksi Briclot