Goblin Electromancer

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

Azami, Lady of Scrolls

Tap an untapped Wizard you control: Draw a card.

Aegar, the Freezing Flame

Whenever a creature or planeswalker an opponent controls is dealt excess damage, if a Giant, Wizard, or spell you controlled dealt damage to it this turn, draw a card.

Archmage Emeritus

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

Riku of Two Reflections

Whenever you cast an instant or sorcery spell, you may pay {U}{R}. If you do, copy that spell. You may choose new targets for the copy.
Whenever another nontoken creature you control enters, you may pay {G}{U}. If you do, create a token that's a copy of that creature.

Arcanis the Omnipotent

{T}: Draw three cards.
{2}{U}{U}: Return Arcanis to its owner's hand.

Cyclone Summoner

When Cyclone Summoner enters, if you cast it from your hand, return all permanents to their owners' hands except for Giants, Wizards, and lands.

Aven Mindcensor

Flash
Flying
If an opponent would search a library, that player searches the top four cards of that library instead.

Kaza, Roil Chaser

Flying, haste
{T}: The next instant or sorcery spell you cast this turn costs {X} less to cast, where X is the number of Wizards you control as this ability resolves.

Jodah, Archmage Eternal

Flying
You may pay {W}{U}{B}{R}{G} rather than pay the mana cost for spells you cast.