Mountain

Forest

Miirym, Sentinel Wyrm

Flying, ward {2}
Whenever another nontoken Dragon you control enters, create a token that's a copy of it, except the token isn't legendary.

Doubling Season

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.
If an effect would put one or more counters on a permanent you control, it puts twice that many of those counters on that permanent instead.

Impact Tremors

Whenever a creature you control enters, Impact Tremors deals 1 damage to each opponent.

Parallel Lives

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.