Ruthless Cullblade

Ruthless Cullblade gets +2/+1 as long as an opponent has 10 or less life.

Duress

Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.

Pyroblast

Choose one —
• Counter target spell if it's blue.
• Destroy target permanent if it's blue.

Smash to Smithereens

Destroy target artifact. Smash to Smithereens deals 3 damage to that artifact's controller.

Electrickery

Electrickery deals 1 damage to target creature you don't control.
Overload {1}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Vampire Neonate

{2}, {T}: Each opponent loses 1 life and you gain 1 life.

Vampiric Fury

Vampire creatures you control get +2/+0 and gain first strike until end of turn. (They deal combat damage before creatures without first strike.)

Chain Lightning

Chain Lightning deals 3 damage to any target. Then that player or that permanent's controller may pay {R}{R}. If the player does, they may copy this spell and may choose a new target for that copy.

Pulse Tracker

Whenever this creature attacks, each opponent loses 1 life.

Guul Draz Vampire

As long as an opponent has 10 or less life, Guul Draz Vampire gets +2/+1 and has intimidate. (It can't be blocked except by artifact creatures and/or creatures that share a color with it.)

Mob Justice

Mob Justice deals damage to target player or planeswalker equal to the number of creatures you control.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Blood Seeker

Whenever a creature an opponent controls enters, you may have that player lose 1 life.

Nihil Spellbomb

{T}, Sacrifice Nihil Spellbomb: Exile target player's graveyard.
When Nihil Spellbomb is put into a graveyard from the battlefield, you may pay {B}. If you do, draw a card.

Mountain

Bloodcrazed Neonate

Bloodcrazed Neonate attacks each combat if able.
Whenever Bloodcrazed Neonate deals combat damage to a player, put a +1/+1 counter on it.