Gruul Signet

Sol Ring

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Command Beacon

{T}: Add {C}.
{T}, Sacrifice this land: Put your commander into your hand from the command zone.

Mountain

Talisman of Impulse

{T}: Add {C}.
{T}: Add {R} or {G}. This artifact deals 1 damage to you.

Arcane Signet

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

Forest

Lotus Petal

{T}, Sacrifice this artifact: Add one mana of any color.

Borborygmos Enraged

Trample
Whenever Borborygmos Enraged deals combat damage to a player, reveal the top three cards of your library. Put all land cards revealed this way into your hand and the rest into your graveyard.
Discard a land card: Borborygmos Enraged deals 3 damage to any target.

Command Tower

Snake Umbra

Enchant creature
Enchanted creature gets +1/+1 and has "Whenever this creature deals damage to an opponent, you may draw a card."
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)