Electrostatic Field

Defender
Whenever you cast an instant or sorcery spell, Electrostatic Field deals 1 damage to each opponent.

Goblin Electromancer

Instant and sorcery spells you cast cost {1} less to cast.

Veyran, Voice of Duality

Magecraft — Whenever you cast or copy an instant or sorcery spell, Veyran, Voice of Duality gets +1/+1 until end of turn.
If you casting or copying an instant or sorcery spell causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Archmage Emeritus

Magecraft — Whenever you cast or copy an instant or sorcery spell, draw a card.