Mountain

Timber Gorge

Timber Gorge enters tapped.
{T}: Add {R} or {G}.

The Howling Abomination

Haste
The Howling Abomination has trample as long as you've cast three or more spells this turn.
Whenever The Howling Abomination becomes the target of a spell, it gets +2/+2 until end of turn and deals 2 damage to each opponent.

Gruul Spellbreaker

Riot (This creature enters with your choice of a +1/+1 counter or haste.)
Trample
During your turn, you and Gruul Spellbreaker have hexproof.

Forest

Migration Path

Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.
Cycling {2} ({2}, Discard this card: Draw a card.)

Jaheira, Friend of the Forest

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

Highland Forest

({T}: Add {R} or {G}.)
Highland Forest enters tapped.

Sapseep Forest

({T}: Add {G}.)
Sapseep Forest enters tapped.
{G}, {T}: You gain 1 life. Activate only if you control two or more green permanents.

Karplusan Forest

{T}: Add {C}.
{T}: Add {R} or {G}. Karplusan Forest deals 1 damage to you.

Traverse the Outlands

Search your library for up to X basic land cards, where X is the greatest power among creatures you control. Put those cards onto the battlefield tapped, then shuffle.