https://www.dlsite.com/books/work/=/product_id/BJ01033241.html

This isn't an omnibus at all..not sure why put that in the naming.

Base +8, Alexandragon +7

dunno i just had to put something in place of 合本版 in the romanized version, please vote to rename if you have a better idea.
By this definition "a book containing reprints of a number of works (as of a single author or on a single subject)" it fits though

Base +7

Searching 合本版 on here gives galleries using "Gappon-ban" as the romanization. Also yeah i guess Omnibus could maybe fit, but usually when i see a Omnibus..it's usually multiple Tank Volumes in a single book

Base +8

Ok, I renamed them for the sake of staying in congruity with the rest of the site, it's just that I've seen the special book terminology in square parenthesis being translated for the romanized script, like 進行中 equating to "ongoing".

Base +7

Way more .jpg compression than the individual chapter uploads.

Base +13