GAV stands for Guile (stealth), Augury (magic) and Vigor (melee).  I have split the favorites list into three columns supporting these three playstyles so that a person can easily maintain and switch different loadouts, as well as have easy access to items on the fly.  The UNSORTED Column has been removed for the Final Release, but there is an optional download available that still has it.

As mentioned, the Menu is sorted into three key components: Guile, Augury and Vigor... each broken down into seven sublists containing all items and abilities that contribute to that type of playstyle.  The sublists break down as follows:

Guile - Daggers, Bows/XBows, Ammunition, Potions, Poisons, Illusion Magic and Light Armour

Augury - Staves, Scrolls, Alteration Magic, Conjuration Magic, Destruction Magic, Restoration Magic and Clothing

Vigor - One Handers, Shields, Two Handers, Shouts and Powers, Tools, Provisions and Heavy Armour

Since the equipment sets available in the original version are not available in the Special Edition (and they were pretty buggy to begin with), this layout should allow you to fairly easily manage different loadouts when the situation demands you switch focus.

HOW TO INSTALL:

Manually download Categorized Favorites Menu and extract the zip file. Copy the favoritesmenu.swf file from that extracted archive to your [Skyrim Root Folder]/data/interface/ folder.  If you haven't done so already, please take the time to endorse Categorized Favorites Menu... favmenumodder deserves it!
Install GAV with NMM or download it manually, extract the zip file and copy favoritesmenu.cfg to your [Skyrim Root Folder]/data/interface/ folder.

HOW TO UNINSTALL:

Delete favoritesmenu.swf from your [Skyrim Root Folder]/data/interface/ folder.
Uninstall GAV with NMM, or manually delete favoritesmenu.cfg from your [Skyrim Root Folder]/data/interface/ folder.
You can install, uninstall or update GAV at any time without negatively impacting your game or your save file. It is completely safe.

ADDING YOUR OWN MODS TO THE MENU:

It isn't too tough to modify the GAV lists yourself. I recommend using Notepad++ to edit the files. You can get it from here: Notepad++. Just navigate to your <Skyrim root folder>\ Data\Interface\ folder and open favoritesmenu.cfg with Notepad++.

The document is fairly easily navigated. Any line with a # at the beginning is a comment and is used to give information to the person reading the document. Any block of text with the line [list] above it is a section denoting a category in the favorites menu, such as "GUILE". A block of text with the line [sublist] above it is a sub-group of that category, such as "Daggers:".

Add, or edit the listings under the corresponding [list] or [sublist] header where you want any new or unsorted items to show up. For example, if you wanted to add a new shout called "I Can Haz Cheeseburger", navigate to the Shouts and Powers section of the document. Hit F3 to open the search option in Notepad++, and type Shouts in the search box that comes up, then hit the "Find Next" button. You are looking for a line that reads "name = Shouts and Powers:" under a [sublist] header. Keep hitting the "Find Next" button until you find the right spot. When you do, you will find a line two or three lines below it that reads "keywords =" then a large block of text separated by semi-colons ( ; ). At the end of this block of text I have placed an entry called (My Mods). Enter a semi-colon then the name "I Can Haz Cheeseburger" without the quotes. All items in the list must be separated by a semi-colon... that is how the program knows how to tell each entry apart. Make sure your spelling is correct.  

I added the entry "(MY MODS)" so that you can easily keep track of which edits were made by you when I update the mod myself.  Before updating to my most recent version, make a backup somewhere handy of the version you are currently using. Then, once you update, copy and paste your edits after the (MY MODS) entry from the backed up version to the new version.

Under each [list] or [sublist] is also a line that reads "excludes =".  You can add entries to this line to help stop items that are showing up in the wrong categories.  Enter the name of an errant item, or enough of a unique portion of that name, to this line to block it from showing up there.

There are three special types of items that you can add that need one extra step: Shouts and powers, two-handed weapons and items that are only used in the left hand.  This is so that their equipping is handled correctly when selected from the favorites menu.  Around 50 or so lines into the favoritesmenu.cfg file are three blocks of text.  The first is prefaced by "two_handed_weapons =", the second is prefaced by "shout_power_names =" and the third is prefaced by "left_hand_equip_only =".  If you add a two handed weapon to the correct category, you also have to add the same name to the end of the block of text after "two_handed_weapons =" in the same way. Shouts or Powers that are activated with the shout key need to be added to the block of text after "shout_power_names =" as well as their category.  Any item, such as a shield or a torch that would only be equipped in the left hand needs to be added to the end of the "left hand only" list as well as its category.

If GAV supports a mod you know you will never use, you can easily remove the keywords for that mod should you ever choose.  I have abbreviated the names of all the mods I have added support for, and entered that name inside brackets before all of the entries needed for it.  To delete support for any mod, just remove all Bracketed names associated with it and the entries that follow.

Another error to look for, aside from items being sorted into the wrong category, is blank lines appearing in categories.  I believe this is caused by conflicts between keywords and excludes lists.  To correct this, search the favoritesmenu.cfg file for common portions of the item listed below the blank line in your favorites list.  If the same item name (or common portion of it) appears in a block of keywords and excludes in the same list you have probably found the culprit.  Try different methods of enforcing the same rules but without the same wording as the two conflicting entries and you should resolve the problem.  

The problem with adding more and more mod support to a favorites list is that it opens up the possibility of more errors popping up... and some of them will be impossible to correct.  Some conflicting mods, or even the same mod, can introduce different items to the game that share the exact same name.  I almost removed support for Legendary Armors - DeserterX collection because all of the armors it adds to the game have a light and heavy variant, but both sets share the exact same name.  Because of this, sorting items from this mod will be incorrect as often as they are correct.  This is not a negative review of the mod in question, as the quality is amazing (although not exactly fitting my current immersive and lore friendly playthrough), but I was pmed a request to add support so I did.

When you are done, exit and save the document. Again, if you have made any additions to the favoritesmenu.cfg file, make sure to back up that file to a convenient place prior to updating so that you don't lose any of your work.

CHANGING THE ON-SCREEN LOCATION OF THE FAVORITES MENU:

On lines 12 and 13 of the layout are the most important variables that allow you to move the placement of the window.  The original version of GAV is optimized to run at a resolution of 1680 x 1050. If you play your game at a different resolution and have found the correct values please let me know so that I can list them here so that other people can easily fix the location of their favorites menu.

The easiest way to adjust the location of the menu is to set your game to run in borderless windowed mode and keep the favoritesmenu.cfg file from your data/interface folder open in Notepad++.   Tweak those two values in Notepad++, then alt-tab back to the game and close and open the favorites menu. Your changes will be adjusted in real time.  Keep this up until you are satisfied with the location.

Resolution        menu_base_x        menu_base_y
1680x1050         20                          -340

CHANGES FROM THE ORIGINAL SKYRIM VERSION:

SKSE was needed for some features of Categorized Favorites Menu. Because of this, they will no longer function in Skyrim Special Edition. Those features are: Equipment Sets and the ability to adjust the look or location of the menu onscreen with hotkeys. The rest of the functionality remains intact and is perfectly safe to use in your game. You can navigate the menu with mouse and keyboard or a controller. You can left click/left trigger or right click/right trigger an item to directly assign it to the left or right hand. And, you can use numbered or d-pad hotkeys to assign quick switch buttons for in-game use.

CUSTOMIZING WEAPON/ARMOR NAMES WHEN ENCHANTING:

There is no way to make GAV recognize every custom name that you give items when you enchant them, but there are a couple simple rules that you can follow to give it a hand. Armor is usually sorted by material /cultural modifier(ie: daedric, elven, iron, etc) whereas weapons and clothing/jewellery are sorted by generic type (ie: sword, war axe, ring, robes, etc.) So, if you use one of those identifiers when naming your custom items, GAV should know where to put it. A chestpiece named Gorvin's Illustrious Orcish Apron would be sorted to heavy armour, whereas an item named Shadowsmasher Mace would be sorted to one handed weapons. Otherwise, you will just have to add the name of your new custom item to the corresponding [sublist] in favoritesmenu.cfg directly.

MOD SUPPORT:

The following mods have had their unique items directly integrated into GAV.  Many other mods not appearing on this list are indirectly supported due to how the keywords are set up.

Immersive Armors
Winter is Coming
Apocalypse - Magic of Skyrim
OBIS - Organized Bandits in Skyrim
Thunderchild - Epic Shouts and Immersion
Sancrosanct - Vampires of Skyrim
Imperious - Races of Skyrim
Expanded Skyrim Weaponry
More Weapons Please
Aurora - Standing Stones of Skyrim
Bandolier Bags and Pouches
Knapsack Backpacks
Leather Backpack
Equippable Tomes
Dagger Craft Package
Regent Armory
Phenderix Magic Evolved
Phenderix Arcane Archery
Immersive Weapons (Original Skyrim Link... not available in SSE yet.)
Cloaks of Skyrim (Original Skyrim Link... not available in SSE yet.)
Wet and Cold
Campfire
Elemental Destruction Magic
Talos Housecarl Armor Pack
Legendary Armors - DeserterX Collection
iNeed - Food Water and Sleep