Viscera Seer

Sacrifice a creature: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Mayhem Devil

Whenever a player sacrifices a permanent, Mayhem Devil deals 1 damage to any target.

Juri, Master of the Revue

Whenever you sacrifice a permanent, put a +1/+1 counter on Juri, Master of the Revue.
When Juri dies, it deals damage equal to its power to any target.

Ignoble Hierarch

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
{T}: Add {B}, {R}, or {G}.

Eternal Witness

When Eternal Witness enters, you may return target card from your graveyard to your hand.

Sol Ring

Plaguecrafter

When Plaguecrafter enters, each player sacrifices a creature or planeswalker of their choice. Each player who can't discards a card.

Priest of Forgotten Gods

{T}, Sacrifice two other creatures: Any number of target players each lose 2 life and sacrifice a creature of their choice. You add {B}{B} and draw a card.

Bedevil

Destroy target artifact, creature, or planeswalker.

Tana, the Bloodsower

Trample
Whenever Tana, the Bloodsower deals combat damage to a player, create that many 1/1 green Saproling creature tokens.
Partner (You can have two commanders if both have partner.)

Mazirek, Kraul Death Priest

Flying
Whenever a player sacrifices another permanent, put a +1/+1 counter on each creature you control.

Caustic Caterpillar

{1}{G}, Sacrifice Caustic Caterpillar: Destroy target artifact or enchantment.

Veil of Summer

Draw a card if an opponent has cast a blue or black spell this turn. Spells you control can't be countered this turn. You and permanents you control gain hexproof from blue and from black until end of turn. (You and they can't be the targets of blue or black spells or abilities your opponents control.)

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Keskit, the Flesh Sculptor

{T}, Sacrifice three other artifacts and/or creatures: Look at the top three cards of your library. Put two of them into your hand and the other into your graveyard.
Partner (You can have two commanders if both have partner.)

Frenzied Trapbreaker

{1}, Sacrifice Frenzied Trapbreaker: Destroy target artifact or enchantment.
Whenever Frenzied Trapbreaker attacks, destroy target artifact or enchantment defending player controls.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Outland Liberator

{1}, Sacrifice Outland Liberator: Destroy target artifact or enchantment.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)