Virtus the Veiled

Partner with Gorm the Great (When this creature enters, target player may put Gorm into their hand from their library, then shuffle.)
Deathtouch
Whenever Virtus deals combat damage to a player, that player loses half their life, rounded up.

Raving Dead

Deathtouch
At the beginning of combat on your turn, choose an opponent at random. This creature attacks that player this combat if able.
Whenever this creature deals combat damage to a player, that player loses half their life, rounded down.

Saryth, the Viper's Fang

Other tapped creatures you control have deathtouch.
Other untapped creatures you control have hexproof.
{1}, {T}: Untap another target creature or land you control.

Family's Favor

Whenever you attack, put a shield counter on target attacking creature. Until end of turn, it gains "Whenever this creature deals combat damage to a player, remove a shield counter from it. If you do, draw a card." (If a creature with a shield counter on it would be dealt damage or destroyed, remove a shield counter from it instead.)

Riveteers Decoy

This creature must be blocked if able.
Blitz {3}{G} (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)

Agent of the Shadow Thieves

Commander creatures you own have "Whenever this creature attacks a player, if no opponent has more life than that player, put a +1/+1 counter on this creature. It gains deathtouch and indestructible until end of turn."

Gorm the Great

Partner with Virtus the Veiled (When this creature enters, target player may put Virtus into their hand from their library, then shuffle.)
Vigilance
Gorm must be blocked if able, and Gorm must be blocked by two or more creatures if able.

Warlock Class

(Gain the next level as a sorcery to add its ability.)
At the beginning of your end step, if a creature died this turn, each opponent loses 1 life.
{1}{B}: Level 2
When this Class becomes level 2, look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.
{6}{B}: Level 3
At the beginning of your end step, each opponent loses life equal to the life they lost this turn. (Damage causes loss of life.)

Quietus Spike

Equipped creature has deathtouch.
Whenever equipped creature deals combat damage to a player, that player loses half their life, rounded up.
Equip {3}

Wound Reflection

At the beginning of each end step, each opponent loses life equal to the life they lost this turn. (Damage causes loss of life.)