Mountain

Ragavan, Nimble Pilferer

Whenever Ragavan deals combat damage to a player, create a Treasure token and exile the top card of that player's library. Until end of turn, you may cast that card.
Dash {1}{R} (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)

Ravenous Baboons

When this creature enters, destroy target nonbasic land.

Arcane Signet

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

Monkey Cage

When a creature enters, sacrifice this artifact and create X 2/2 green Monkey creature tokens, where X is that creature's mana value.

Sol Ring

Prickly Marmoset

First strike
Whenever you cycle a card, this creature gets +2/+0 until end of turn.

Clockwork Percussionist

Haste
When this creature dies, exile the top card of your library. You may play it until the end of your next turn.

Simian Sling

Equipped creature gets +1/+1.
Whenever this creature or equipped creature becomes blocked, it deals 1 damage to defending player.
Reconfigure {2} ({2}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)