Stormsplitter and Sorcerer Class on the battlefield.
Sorcerer Class is at least level 2.
({16} magic symbol) at most, depending on how many Stormsplitters and/or other creatures you control without summoning sickness available.
Steps
Activate any creature you control that does not have summoning sickness by tapping it, adding ({U} magic symbol) that can only be spent to cast an instant or sorcery spell, or to gain a Class level.
Repeat step 1 until you control no untapped creatures without summoning sickness, or until you have ({5} magic symbol) ({U} magic symbol) available, whichever comes first.
Cast Whispers of the Muse with buyback by paying ({5} magic symbol) ({U} magic symbol) .
Each Stormsplitter you control triggers, and Sorcerer Class's third ability triggers if it is level 3.
Resolve the Stormsplitter triggers, creating that many token copies of Stormsplitter.
Resolve the Sorcerer Class trigger, if applicable, dealing damage to any target equal to the number of instant and/or sorcery spells you've cast this turn.
Resolve Whispers of the Muse, causing you to draw a card, and return Whispers of the Muse to your hand.
Repeat.
Results
Infinite card draw.
Infinite draw triggers.
Near-infinite damage.
Near-infinite ETB.
Near-infinite storm count.
Near-infinite LTB.
Near-infinite magecraft triggers.
Near-infinite creature tokens with haste.
Near-infinite blue mana that can only be spent to cast instant and/or sorcery spells.
Near-infinite red mana that can only be spent to cast instant and/or sorcery spells.