The arcane tradition of Spell Permutation is a fan subclass for 5e's wizard class. This tradition builds and improves on one of the wizard's key trait - spell versatility. Practitioners of that tradition are commonly called permuters.

There are two themes: allowing permuters to cast known but not prepared spells, and encouraging them to vary their spell choices, both at preparation time and at casting time. These two themes are designed to complement each other.

Features

Spell Rearrangement You learn how to more speedily prepare spells. Starting at 2nd level when you choose this school, when you use your Arcane Recovery feature to regain spell slots, you may also change your prepared spell list as if you have just finished a long rest.

Spontaneous Casting You know how to manipulate your preparations on-the-fly to satisfy the requirements for other spells. Starting at 2nd level when you choose this school, you may cast any non-cantrip spell that you have in your spellbook, even if you do not have that spell prepared. The spell uses a spell slot as usual. Once you cast a spell this way, you cannot do so again until you finish a short or long rest.

School Resonance You learn how to spot and utilize residual energy from your spellcasting, in order to enhance complementing follow-up spells. Starting at 6th level, after you cast a spell on your turn using a spell slot, you may use a bonus action to randomly choose a school of magic by rolling a d8 on the table below. Result School 1 Abjuration 2 Conjuration 3 Divination 4 Enchantment 5 Evocation 6 Illusion 7 Necromancy 8 Transmutation When you do so, for the next minute, the first time you cast a spell of that school using a spell slot between level 1 and 5, it assumes a spell level 1 level higher than the slot used to cast it.

Improved Spontaneous Casting You master the ability to adapt and mutate your preperations on the spot. Starting at 10th level, you may now use Spontaneous Casting a number of times equals to your intelligence modifier (a minimum of 1) between short or long rests.