Glissa, the Traitor

First strike, deathtouch
Whenever a creature an opponent controls dies, you may return target artifact card from your graveyard to your hand.

Perilous Myr

When Perilous Myr dies, it deals 2 damage to any target.

Night of Souls' Betrayal

Heartless Summoning

Creature spells you cast cost {2} less to cast.
Creatures you control get -1/-1.

Ugin, the Ineffable

Colorless spells you cast cost {2} less to cast.
+1: Exile the top card of your library face down and look at it. Create a 2/2 colorless Spirit creature token. When that token leaves the battlefield, put the exiled card into your hand.
−3: Destroy target permanent that's one or more colors.

Shimmer Myr

Flash
You may cast artifact spells as though they had flash.

Glissa Sunseeker

First strike
{T}: Destroy target artifact if its mana value is equal to the amount of unspent mana you have.