Tendrils of Agony

Target player loses 2 life and you gain 2 life.
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)

Headstone

Exile target card from a graveyard.
Draw a card at the beginning of the next turn's upkeep.

Priest of Gix

When Priest of Gix enters, add {B}{B}{B}.

Skirge Familiar

Hullbreaker Horror

Flash
This spell can't be countered.
Whenever you cast a spell, choose up to one —
• Return target spell you don't control to its owner's hand.
• Return target nonland permanent to its owner's hand.

Professor Onyx

Magecraft — Whenever you cast or copy an instant or sorcery spell, each opponent loses 2 life and you gain 2 life.
+1: You lose 1 life. Look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.
−3: Each opponent sacrifices a creature with the greatest power among creatures that player controls.
−8: Each opponent may discard a card. If they don't, they lose 3 life. Repeat this process six more times.

Aphotic Wisps

Target creature becomes black and gains fear until end of turn. (It can't be blocked except by artifact creatures and/or black creatures.)
Draw a card.

Rona, Sheoldred's Faithful

Whenever you cast an instant or sorcery spell, each opponent loses 1 life.
You may cast Rona, Sheoldred's Faithful from your graveyard by discarding two cards in addition to paying its other costs.

Chain of Smog

Target player discards two cards. That player may copy this spell and may choose a new target for that copy.

Brain Freeze

Target player mills three cards.
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)