Rakuen:
Sprites:
Tadm: Adam Black
Trby: ロビー嫁 (robii yome) is written over some (unused) sprites, which means "Robbie's Wife", that being Zoey Graham. (It also matches with the used sprites, not just by code.)
Ttra: Travis, Oslo's right hand man
Edit: tpo: Typhoon
Tyam: Yamamoto. He was the one who sold the gun to Makina via Thanatos/Kazuki. Not sure if you have enough to explain in parentheses if you want.

Other:
blam*/cm.png: Movie thumbnails for the movie gallery. You can move them to User Interface, since that is what you did with the movie thumbnails for Kajitsu.
dac010a.png: I don't know what to think of this. It seems to be a mispelling of dav but a dav010a exists and it has a corresponding thumbnail *_m.png so I don't know how this is what it is. It can stay unidentified.
SDevent*/sdevent*: Seems to be the equivalent of ./Main Story/Chibi, so it would be wise to move there. (That folder does not exist yet.)
sekaiproject_1280.png: Logo? Shouldn't it be moved to logos?
Edit2: tri_planeL.png/tri_planeR.png/tri_planeT.png: Left, Right, and Top (presumably) of something regarding a plane. Can probably stay unidentified.

Grisaia no Senritsu
The only files in Unidentified are those obt* files. They are basically objects on the screen which are shown over the current background. Not sure if you want to move these out of Unidentified or keep it there.

Grisaia no Zankou:
The only files in Unidentified are the sprites for Yamamoto.

This should be all the identifications you need for identifying everything. (All that would be remaining would be testimage.png in Kajitsu/Meikyuu - which doesn't really need identifying - and whatever is unidentified in Yuukan and IMGCCM - since I don't own those.)

It would be a good idea to mention that, because this is command-based, you can make a paste script. For an example I have a txt file that extracts all pcm*.int files from Grisaia no Kajitsu separately and puts them in appropriate output folders. You can, of course, change the sources or destinations by editing the file. If the source was detected automatically, you can remove the contents of the line (but not the line itself).
All you have to do to execute the "paste script" (as I call it) is paste the contents of the text file in the application.

The only con to said "paste scripts" is that each task is done one after the other so it does not have a cumulative time (but that's a feature you added yourself for multiple extractions or extraction and conversion in a single attempt, so I guess it can be a nonissue).

Edit: I don't know what you mean by the enhancement tag, since what I mentioned can be done now with the current version. (I just wanted to make that clear even though I already said as much.)

Edit 2: I read the description of it and now understand.

The first may be a Windows-related issue but I am not familiar with this error.
The data area passed to a system call is too small. (Exception from HRESULT: 0x8007007A) If it helps, the game I tried extracting from was Grisaia no Meikyuu.

The second issue is that sometimes it stops converting and closes without error nor confirmation when converting hg3 files. It is consistent on when and where it crashes but not every game has hg3 files that crash upon attempting to convert.

If it also matters, I am running the application on a Windows 10 x64 laptop.

I'm going through the files in Meikyuu, changing the sorting to how I personally would have the folder structure, and I'm noticing that SD is not caught in sd things, for chibi.

Most of the images are coming off as a part of the Unidentified folder, likely due to not considering characters take place exclusively in this game like sprites for Major Isabella Fitzgerald (iza), Marion Garland (mro), and Ramon Noboa (nob). There are also some BGs with the prefix bgt which are backgrounds not placed in the background folder. The CGs are given the prefix evt, which are also placed in Unidentified. You can have them in a Story/CG directory like you do for Afterglow (Zankou).

I'm sorry to post a issue concerning others' code here, but it seems that this is the only place I found that uses asmodean's code.

The problem is: I cannot find any header files the source code references, and I couldn't guess how certain functions work without them, especially functions in the "as::" namespace.

The question is: How did you work around it? I would really need some help in understanding the code...

Thanks SO much for looking at this off-topic issue anyway.