This UESP link explains batch (.bat) files if you're new to the concept

Instructions

Download the file manually

Open the .zip file until you have the .txt file

Move/Copy the .txt file to your Skyrim Directory (usually located at C:\Program Files (x86)\Steam\steamapps\common\Skyrim)

Feel free to delete the now empty .zip file

Open Skyrim and load your preferred save

Open the console (with the tilde key, it looks like ~ or `)

Type "bat allspelltomes" and hit Enter

All spell tomes should then be added to your inventory

If I missed any, please let me know and I'll try and fix it right away

Extra Info (DLC Spell Tome)

The only spell tome added by an official DLC is the "Conjure Ash Guardian" for Dragonborn

To add that to your inventory, simply type "player.additem 0401AABA 1"

If the console says that Object ID is missing, read up on using "xx" in console commands (or see the screenshots of the article above)

Optional Files

I added files for tomes in each magic class, in case some users only wanted tomes from a certain class

Instructions are all the same except the console commands, type:
"bat illspelltomes" for Illusion tomes
"bat conspelltomes" for Conjuration tomes
"bat desspelltomes" for Destruction tomes
"bat resspelltomes" for Restoration tomes
"bat altspelltomes" for Alteration tomes

Other Mods
Add All Skill Books