Mountain

Forest

Terramorphic Expanse

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Street Urchin

Commander creatures you own have "{1}, Sacrifice another creature or an artifact: This creature deals 1 damage to any target."

Darksteel Plate

Indestructible
Equipped creature has indestructible.
Equip {2}

Erinis, Gloom Stalker

Deathtouch
Whenever Erinis attacks, return target land card from your graveyard to the battlefield.
Choose a Background (You can have a Background as a second commander.)

Arcane Signet

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

Sol Ring

Krenko, Mob Boss

{T}: Create X 1/1 red Goblin creature tokens, where X is the number of Goblins you control.