So, what do you do if you're Fred Fish, founder of a legendary floppy-disk line and prolific purveyor of CD-ROMs?
You keep making them, of course. Fresh Fish is Fred's line of CD-ROMs for people who are looking for something rather specific in a CD.
In this case, if you're looking for Fresh Fish, you're probably a programmer, or at least somebody who will make something useful out of the hundreds of megs of GNU source code and Commodore development tools (V37-V40 of the NDUK material as well as the old RKRMs from a Fred Fish disk.)
To keep you busy in the meantime (and fill up space, but shhh, don't tell) are the entire catalogs of all Fish disks (and other CD-ROM lines), the comp.sys.amiga.reviews FTP site snapshot, and a good 100 megs or so of "useful" programs (conveniently and familiarly set into an Aminet-like hierarchy.) In short, this is the way Fred keeps taking the submissions he originally became famous for, but now there's no hassling with floppies.
As a source for development tools, includes, libraries, source, etc. you can't go wrong. Entire language compiler packages can be found here. The Commodore stuff isn't bad, either...after all, it's not like you can call up CATS looking for it. The fact that everything (except some C= material and some other restrictions) is packed-and-ready for BBSes helps as well.
If you're just looking for "cool stuff on a CD-ROM", though, there are better choices.