Scorched Rusalka

{R}, Sacrifice a creature: Scorched Rusalka deals 1 damage to target player or planeswalker.

Cathartic Reunion

As an additional cost to cast this spell, discard two cards.
Draw three cards.

Welder Automaton

{3}{R}: Welder Automaton deals 1 damage to each opponent.

Kruin Striker

Whenever another creature you control enters, Kruin Striker gets +1/+0 and gains trample until end of turn.

Razortrap Gorge

Razortrap Gorge enters tapped unless a player has 13 or less life.
{T}: Add {B} or {R}.

Swamp

Goblin Matron

When Goblin Matron enters, you may search your library for a Goblin card, reveal that card, put it into your hand, then shuffle.

Thrill of Possibility

As an additional cost to cast this spell, discard a card.
Draw two cards.

Impact Tremors

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

Drossforge Bridge

Drossforge Bridge enters tapped.
Indestructible
{T}: Add {B} or {R}.

Mountain

First Day of Class

Whenever a creature you control enters this turn, put a +1/+1 counter on it and it gains haste until end of turn.
Learn. (You may reveal a Lesson card you own from outside the game and put it into your hand, or discard a card to draw a card.)

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Skirk Prospector

Putrid Goblin

Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)