Goblin Guide

Haste
Whenever Goblin Guide attacks, defending player reveals the top card of their library. If it's a land card, that player puts it into their hand.

Goblin Bombardment

Sacrifice a creature: Goblin Bombardment deals 1 damage to any target.

Mogg Bombers

When another creature enters, sacrifice Mogg Bombers and it deals 3 damage to target player or planeswalker.

Ral's Reinforcements

Create two 1/1 blue and red Elemental creature tokens.

Heartfire Immolator

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
{R}, Sacrifice this creature: It deals damage equal to its power to target creature or planeswalker.

Valakut Exploration

Landfall — Whenever a land you control enters, exile the top card of your library. You may play that card for as long as it remains exiled.
At the beginning of your end step, if there are cards exiled with Valakut Exploration, put them into their owner's graveyard, then Valakut Exploration deals that much damage to each opponent.

Soul-Scar Mage

Prowess
If a source you control would deal noncombat damage to a creature an opponent controls, put that many -1/-1 counters on that creature instead.

Monastery Swiftspear

Haste
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Goblin Javelineer

Haste
Whenever Goblin Javelineer becomes blocked, it deals 1 damage to target creature blocking it.

Young Pyromancer

Whenever you cast an instant or sorcery spell, create a 1/1 red Elemental creature token.

Torbran, Thane of Red Fell

If a red source you control would deal damage to an opponent or a permanent an opponent controls, it deals that much damage plus 2 instead.