Gorgon's Head

Equipped creature has deathtouch.
Equip {2}

Akiri, Line-Slinger

First strike, vigilance
Akiri gets +1/+0 for each artifact you control.
Partner (You can have two commanders if both have partner.)

Basilisk Collar

Equipped creature has deathtouch and lifelink. (Any amount of damage it deals to a creature is enough to destroy it. Damage dealt by this creature also causes you to gain that much life.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Rograkh, Son of Rohgahh

First strike, menace, trample
Partner (You can have two commanders if both have partner.)

Jeska, Thrice Reborn

Jeska enters with a loyalty counter on her for each time you've cast a commander from the command zone this game.
0: Choose target creature. Until your next turn, if that creature would deal combat damage to one of your opponents, it deals triple that damage to that player instead.
−X: Jeska deals X damage to each of up to three targets.
Jeska, Thrice Reborn can be your commander.
Partner

Gorgon Flail

Equipped creature gets +1/+1 and has deathtouch. (Any amount of damage it deals to a creature is enough to destroy that creature.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Hedron Blade

Equipped creature gets +1/+1.
Whenever equipped creature becomes blocked by one or more colorless creatures, it gains deathtouch until end of turn. (Any amount of damage it deals to a creature is enough to destroy it.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)