Maraxus of Keld

Maraxus of Keld's power and toughness are each equal to the number of untapped artifacts, creatures, and lands you control.

Jaddi Lifestrider

When Jaddi Lifestrider enters, you may tap any number of untapped creatures you control. You gain 2 life for each creature tapped this way.

Forest

Into the Maw of Hell

Destroy target land. Into the Maw of Hell deals 13 damage to target creature.

Hogaak, Arisen Necropolis

You can't spend mana to cast this spell.
Convoke, delve (Each creature you tap while casting this spell pays for {1} or one mana of that creature's color. Each card you exile from your graveyard pays for {1}.)
You may cast Hogaak, Arisen Necropolis from your graveyard.
Trample

Plaguebearer

{X}{X}{B}: Destroy target nonblack creature with mana value X.

Tarmogoyf

Tarmogoyf's power is equal to the number of card types among cards in all graveyards and its toughness is equal to that number plus 1.

Thundermare

Haste (This creature can attack and {T} as soon as it comes under your control.)
When Thundermare enters, tap all other creatures.

Skull Storm

When you cast this spell, copy it for each time you've cast your commander from the command zone this game.
Each opponent sacrifices a creature of their choice. Each opponent who can't loses half their life, rounded up.