This is an archive for various arcade hacks, usually by users like Yumeji, Ydmis, Pipi899 and that sort, these are usually hard to find and only work on ancient FBA exes from 2009, and that's when you even find them beyond dead 4shared links.
The files are in IPS format for the purposes of softpatching with FBN proper, with DAT files and everything
To use them with Libretro, you need to patch the files you want, each IPS file is named for the exact file you need to patch, then put it in this path
"/"wherever you store your install or settings"/retroarch/system/fbneo/patched
The rom name has to be the same as whatever you use as a base, so if you use kof98.zip and patch it's files, you use the base kof98 rom without renaming either, some roms require different bases so I'm gonna compile a document together as a cheat sheet for what rom uses which patch to make it easier.
There's also instructions for running this with standalone FBN, Fightcade is untested though.
These are sourced from HBMame's .233 romset, the hacks are primarily for playing as bosses and hidden characters in fighting games but I convert any hack I find that's neat, like the Blazing Star Stage Select or a Metal Slug 5 remake someone did, there's also a document in there with relevant info.
As a bonus, aside from one hack for Kof97, which is natively supported as a Playstation imitation hack, the Neo Geo hacks can be run in both MVS and AES mode so if you prefer one or the other then you can do so, the Playstation hack I mentioned only works with AES mode.