Mountain

Unsummon

Return target creature to its owner's hand.

Target creature can't be blocked this turn.
Flashback {U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Switch target creature's power and toughness until end of turn.
Draw a card.

Whenever you cast an instant or sorcery spell, Festival Crasher gets +2/+0 until end of turn.

Flying, haste
Whenever you cast a noncreature spell, put a +1/+1 counter on Sprite Dragon.

Spikefield Cave enters the battlefield tapped.
{T}: Add {R}.

Spikefield Hazard deals 1 damage to any target. If a permanent dealt damage this way would die this turn, exile it instead.

Whenever you cast an instant or sorcery spell, Kiln Fiend gets +3/+0 until end of turn.

Target creature gains haste until end of turn.
Draw a card.

Add two mana in any combination of colors.
Draw a card.