Blisterspit Gremlin

{1}, {T}: This creature deals 1 damage to each opponent.
Whenever you cast a noncreature spell, untap this creature.

Thermo-Alchemist

Defender
{T}: This creature deals 1 damage to each opponent.
Whenever you cast an instant or sorcery spell, untap this creature.

At the beginning of each player's upkeep, this enchantment deals damage to that player equal to the number of artifacts they control.

Landfall — Whenever a land you control enters, this creature deals 1 damage to each opponent.

Alliance — Whenever another creature you control enters, this creature deals 1 damage to each opponent.

Whenever you cast a noncreature spell, this creature deals 1 damage to each opponent.

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Whenever another creature dies, you may have this creature deal 1 damage to target player or planeswalker.