Gruul Charm

Choose one —
• Creatures without flying can't block this turn.
• Gain control of all permanents you own.
• Gruul Charm deals 3 damage to each creature with flying.

Arcane Signet

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

Mountain

Sol Ring

Gruul Signet

Gruul Cluestone

{T}: Add {R} or {G}.
{R}{G}, {T}, Sacrifice Gruul Cluestone: Draw a card.

Skred

Skred deals damage to target creature equal to the number of snow permanents you control.

Svella, Ice Shaper

{3}, {T}: Create a colorless snow artifact token named Icy Manalith with "{T}: Add one mana of any color."
{6}{R}{G}, {T}: Look at the top four cards of your library. You may cast a spell from among them without paying its mana cost. Put the rest on the bottom of your library in a random order.

Gruul War Plow

Creatures you control have trample.
{1}{R}{G}: Gruul War Plow becomes a 4/4 Juggernaut artifact creature until end of turn.

Rime Tender

{T}: Untap another target snow permanent.

Forest

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Agatha of the Vile Cauldron

Activated abilities of creatures you control cost {X} less to activate, where X is Agatha of the Vile Cauldron's power. This effect can't reduce the mana in that cost to less than one mana.
{4}{R}{G}: Other creatures you control get +1/+1 and gain trample and haste until end of turn.

Conifer Wurm

Trample
{3}{G}: Conifer Wurm gets +X/+X until end of turn, where X is the number of snow permanents you control.