That's not unpossible.To qualify for all those Multiclasses you would need standard Human. (14, 14, 14, 13, 13, 13)
Barbarian Unarmed Defense, Rage, Fighting Style - Dueling, Monk Martial Arts,Sneak Attack
Using a Shortsword, you can rage and deal 2d6+6, and then in subsequent turns deal another 1d6+4 unarmed attack.
And then you've got 6 spell slots and a crazy amount of prepared level spells, including a lot of reaction ones.
A barbarian/bard/cleric/fighter/monk/paladin/ranger/rogue/sorcerer/warlock/wizard.
A barbarian/bard/cleric/fighter/monk/paladin/ranger/rogue/sorcerer/warlock/wizard.
I happen to love multiclasses, and I happen to love taking things that supposedly don't work together, and make them interesting.
So give me a multiclass combination that you believe kills the character, and I'll try to create a character that changes your mind.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.