Mizzix of the Izmagnus

Whenever you cast an instant or sorcery spell with mana value greater than the number of experience counters you have, you get an experience counter.
Instant and sorcery spells you cast cost {1} less to cast for each experience counter you have.

Scour from Existence

Fire

Fire deals 2 damage divided as you choose among one or two targets.

Fire // Ice

Volt Charge

Volt Charge deals 3 damage to any target. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Capsize

Buyback {3} (You may pay an additional {3} as you cast this spell. If you do, put this card into your hand as it resolves.)
Return target permanent to its owner's hand.

Prophetic Bolt

Prophetic Bolt deals 4 damage to any target. Look at the top four cards of your library. Put one of those cards into your hand and the rest on the bottom of your library in any order.

Pyroblast

Choose one —
• Counter target spell if it's blue.
• Destroy target permanent if it's blue.

Nivmagus Elemental

Exile an instant or sorcery spell you control: Put two +1/+1 counters on this creature. (That spell won't resolve.)

Radiate

Choose target instant or sorcery spell that targets only a single permanent or player. Copy that spell for each other permanent or player the spell could target. Each copy targets a different one of those permanents and players.

Part the Waterveil

Take an extra turn after this one. Exile Part the Waterveil.
Awaken 6—{6}{U}{U}{U} (If you cast this spell for {6}{U}{U}{U}, also put six +1/+1 counters on target land you control and it becomes a 0/0 Elemental creature with haste. It's still a land.)