Ellie, Brick Master

Distract the Horde — Whenever a player attacks one of your opponents, that attacking player creates a tapped 1/1 black Fungus Zombie creature token named Cordyceps Infected that's attacking that opponent.
Partner—Survivors (You can have two commanders if both have this ability.)

Mycoloth

Devour 2 (As this creature enters, you may sacrifice any number of creatures. It enters with twice that many +1/+1 counters on it.)
At the beginning of your upkeep, create a 1/1 green Saproling creature token for each +1/+1 counter on this creature.

Unleash Fury

Double the power of target creature until end of turn.

Abby, Merciless Soldier

When you cast this spell, create a number of 1/1 black Fungus Zombie creature tokens named Cordyceps Infected equal to the amount of mana spent to cast it.
Abby enters under the control of an opponent of your choice.
Partner—Survivors (You can have two commanders if both have this ability.)

Wild Growth

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional {G}.

Joel, Resolute Survivor

Menace
Whenever a creature token dies, put a +1/+1 counter on Joel and draw a card. This ability triggers only once each turn.
Partner—Survivors (You can have two commanders if both have this ability.)

Ellie, Vengeful Hunter

Pay 2 life, Sacrifice another creature: Ellie deals 2 damage to target player and gains indestructible until end of turn.
Partner—Survivors (You can have two commanders if both have this ability.)

Dictate of Erebos

Flash
Whenever a creature you control dies, each opponent sacrifices a creature of their choice.

Cabal Ritual

Add {B}{B}{B}.
Threshold — Add {B}{B}{B}{B}{B} instead if there are seven or more cards in your graveyard.

Haunted One

Commander creatures you own have "Whenever this creature becomes tapped, it and other creatures you control that share a creature type with it each get +2/+0 and gain undying until end of turn." (When a creature with undying dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)