Slinza, the Spiked Stampede

Beast spells you cast cost {2} less to cast.
Each other Beast creature you control enters with an additional +1/+1 counter on it.
Whenever Slinza or another creature with power 4 or greater enters, you may pay {1}{R/G}. When you do, Slinza fights target creature you don't control.

Forest

Arcane Signet

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

Mountain

Sol Ring

Gruul Signet

Talisman of Impulse

{T}: Add {C}.
{T}: Add {R} or {G}. Talisman of Impulse deals 1 damage to you.