Venerated Rotpriest

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
Whenever a creature you control becomes the target of a spell, target opponent gets a poison counter.

Denizen of the Deep

When Denizen of the Deep enters, return each other creature you control to its owner's hand.

Path of Ancestry

Path of Ancestry enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Power Word Kill

Destroy target non-Angel, non-Demon, non-Devil, non-Dragon creature.

All-Seeing Arbiter

Flying
Whenever All-Seeing Arbiter enters or attacks, draw two cards, then discard a card.
Whenever you discard a card, target creature an opponent controls gets -X/-0 until your next turn, where X is the number of different mana values among cards in your graveyard.

Deicide

Exile target enchantment. If the exiled card is a God card, search its controller's graveyard, hand, and library for any number of cards with the same name as that card and exile them. Then that player shuffles.

Obliterate

This spell can't be countered.
Destroy all artifacts, creatures, and lands. They can't be regenerated.

Calamity's Wake

Exile all graveyards. Players can't cast noncreature spells this turn. Exile Calamity's Wake.