Well, I might as well release this now then.
It's a Character Editor. (Internal project name "One AOB to Rule Them All, One AOB to Find Them", or "One AOB" for short.)
Also includes a fix for the Buff Timer Overlay. All you need to do is first load Squall's table, then load and merge this one. (Both Overlays and their related scripts don't seem to cause crashes.)
It includes many things by other authors, brought under one roof.
Seikur0 - Character Data, Palico Data, Character Appearance, Palico Appearance, Mission Stats
Squall - Weapon Usage, Monster Kills/Captures, Monster Research Level/XP, Monster Size
Marcus101R - Investigation data format
Idlehands88 - Give All Items
Then there's my stuff, the suite of Inventory Editors - Item Pouch, Item Box, Hunter Equipment, Palico Equipment, and Arena Equipment. (Along with a bunch of other stuff of debatable usefulness.)
Item Pouch has a ghetto Inf Item Use function I made after the last update.
You can swap and remove items freely except for those that only have 1 in the stack, which can only be swapped. To remove them, you will need fill it up to 2 or more, or for items with 1 maximum stack size, swap it with something else and then remove.
Item Box has a search function, which can be used to quickly(-ish) find the item you want in the inventory.
I made a prototype Hunter Equipment Inventory Editor 2.5 months ago (literally a week after PC release), but the current version (last updated a month ago - been doing other stuff since) has been refined quite a bit. Features fully categorized drop-down lists, and search functions to find ones already in your inventory.
All search functions work by setting the search param, then enabling the search script. The result entry below will show the result, and if found, the relevant editor will now be selecting the desired item.
With the Arena Equipment, you can now do Arena and Challenge quests using whatever gear you want. Just set them up and freeze the values. They'll be saved too, so you don't need to set them up from scratch constantly, as long as you freeze them before accessing Arena quests.
Specialized Tools don't have an inventory entry (except in the Arena) and should be changed from the "Equipped Item Index" drop-down list. (You can even use Tools that you don't have yet, like the Temporal Mantle.)
Everything can be changed from anywhere, even from the main menu. To immediately save the changes from there without going into character selection, just go into options and then come back out. (Useful when you accidentally changed an item you're wearing into something that crashes the game and saved.)
*Edit: Investigation Editor has something called the "Quick ID", which, as the name implies, can be used to quickly identify which map, rank and monster the investigation has. As labeled, do NOT use it to actually change things. That requires the back part, which gets encrypted on every game load and messes with the full entry's ability to identify what it is. The Quick ID works by only checking the front part that isn't encrypted.
The editor also only updates every 1 second, so it may take up to 1 second for the editor to actually select the item you tell it to select.
*Edit2: Newest version here