Allister's Wondrous Library

The caster summons an ethereal library that has the ability to store up to 25 spell books, 30 spell scrolls, 100 non magical books, 1000 gp worth of enchanted ink, and 500 gp worth of premium paper.

This space cannot be accessed by anyone, but the caster or whom the caster allows to have access. The space cannot be closed while the caster or any creature are inside of it. The gate of the space will reject any who try to enter without permission by gently pushing them back the first 2 times, but violently the 3rd time. (DM's digression if it does any sort of bludgeoning damage on the push). (Can be cast as a ritual spell out of combat to access the space.)

In combat this space can be brought forth in the form of an ethereal bookshelf floating above the caster's head. The caster can then use their bonus action to bring forth a random spell book or scroll from their collection to use in battle after they summon the space. They can choose between book or scroll prior to rolling on the Random Spell Table. 

As a bonus action you can use the spell that was randomly chosen on your next turn in battle. You can continue to use that spell without using a spell slot for 2 turns when the spell is casted at 3rd level and +1 turn per higher spell slot used. Once the end of the predetermined amount of turns ends, the book closes and is returned to the library. The spells chosen from spell books within cannot be higher than 3rd level or the spell will fail. Furthermore, the caster can choose to use their action to reroll on the Random Spell Table to receive a different spell anytime so long as their concentration has not been broken or until the spell ends.

Any level of spell scrolls can be stored within the library, and used by the caster in battle with the same rules above. However, upon use the spell scroll of the caster's choice burns up into ash, and does not return to the library. The caster must use their action to summon forth another spell scroll of their choice if they choose to do so, as long their concentration has not been broken or until the spell ends. 

The caster is responsible for filling out spell books to use, as well as providing the empty book, magic ink, and spell scroll they wish to transcribe. You can copy spells you already have transcribed in your personal spell book to another blank book for just the cost of ink and time. Each book can contain 10 spells. A book cannot be added to the library if there is not 10 spells transcribed within the book. If a spell component of a certain value is needed for the spell, then the components will be consumed upon casting. If the caster does not have the components required then the book will shut and return to the library. The caster is responsible for keeping track of the spells in each book.

Table Rules: Roll 1d6 for the Collection you wish to pick from. Does not apply if you don't have books in all 5 collections. Use a corresponding sided dice for the amount of collections you have books stored in. The same rules apply when rolling for which book. Roll 1d10 to choose which spell you will be using from your selected book.

(Players, please be sure to have a naming convention for all of your books that you and your DM agree on. It doesn't need to be creative. Just make sure it makes sense to you. i.e. Codex1, Codex2, etc. Be creative if you like of course.)

(DM's, please be sure to have your player share their spell and book tables with you once they create them. This is a difficult, and mind numbing spell to keep track of if you and your player aren't on the same page. This is a spell that's meant to be complex, since Wizards should be complex, and intelligent people. This by no means is supposed to be a spell that becomes viable immediately. Its meant to be a down time activity that one will benefit from as their journey goes on. Feel free to write your hate comments later lol.)