Gruul Signet

Birds of Paradise

Harness the Storm

Whenever you cast an instant or sorcery spell from your hand, you may cast target card with the same name as that spell from your graveyard. (You still pay its costs.)

Slime Against Humanity

Create a 0/0 green Ooze creature token with trample. Put X +1/+1 counters on it, where X is two plus the total number of cards you own in exile and in your graveyard that are Oozes or are named Slime Against Humanity.
A deck can have any number of cards named Slime Against Humanity.

Goblin Anarchomancer

Each spell you cast that's red or green costs {1} less to cast.

Raggadragga, Goreguts Boss

Each creature you control with a mana ability gets +2/+2.
Whenever a creature you control with a mana ability attacks, untap it.
Whenever you cast a spell, if at least seven mana was spent to cast it, untap target creature. It gets +7/+7 and gains trample until end of turn.

Arcane Signet

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

Emerald Medallion

Green spells you cast cost {1} less to cast.

Delighted Halfling

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a legendary spell, and that spell can't be countered.

Three Visits

Search your library for a Forest card, put it onto the battlefield, then shuffle.

Cryptolith Rite

Creatures you control have "{T}: Add one mana of any color."

Elvish Mystic

Vitalize

Jaheira, Friend of the Forest

Tokens you control have "{T}: Add {G}."
Choose a Background (You can have a Background as a second commander.)

Nature's Lore

Search your library for a Forest card, put that card onto the battlefield, then shuffle.