--NOTE: All data file edits require this file in order to prevent the "Game files have been modified" error.
Various things from the old forum:
Tiga De Ragan board fix. (Makes it require Par Ork instead of the normally-unavailable Arti Diga).
PSP1: player stats, monster stats (remove the _psp1 at the end). These will not be supported at all in the future and do not have proper stats above character level 100, they're just a novelty.
PSP2i: player stats, monster stats. (Remove the _psp2i at the end). These are unsupported and _hilariously unbalanced_ (didn't alter the individual monsters or the tech/PA multipliers), use at your own risk.
New stuff:
Item addon. They don't drop, but this will enable pretty much all of the standard AotI weapons (only one per model; kubara copies have placeholder stats) and room decorations if you want to cheat for them (there are guides pretty much all over the place for this). Note that it is not compatible with the PSP1/2i stats!
Modified .exe and data file. Same as above, but enables advanced types. NOTE: they have placeholder stats, but if you use the data file, they'll have their online weapon proficiencies. (File not being supported).
Mission pack 4/cumulative mission pack
Mission pack 5 (you should probably play this one) (requires mission pack 4 and a Japanese game installation directory)
Things to expect in the future:

Reworked APCs!

Story missions!

Supplemental/third update content!
(This is the one that requires breaking compatibility with the standard files; you cannot possibly fit 75 Kubara sabers into 20 weapon slots).