https://macintoshgarden.org/apps/fantasm-6
Is that along the lines of what is wanted?
Yes, I had hunt down the * out of anything Fantasm-related on the Mac after Naiw's mentioning of it to me years back in some thread about programming aspirations and languages for Mac. That link is to a page I prepared with great care myself (Jubadub here = Jatoba on the Garden), after collecting everything I could. I also updated the pages for all the older versions
on the Mac that predate version 6, some of which contain a few cool extras (i.e. 68k Assembly Guide, goes great alongside their PPC Assembly Guide, plus lots of demos, docs etc.). Apparently Fantasm (FANTasy ASseMbler) started out on the Atari ST, but I haven't bothered to track
that down.
We are still missing the commercial, CD release of Fantasm 6, though. It ought to have some extra goodies. We are also missing LXT 2 (LXT2.00Apr99.sit.hqx), as mentioned on the page, although we have LXT Carbon, which should hopefully be the same, hopefully also with improvements, but Carbonized.
LXT is basically a macro collection to translate 68k assembly into equivalent PPC assembly. IIRC it is editable, meaning if you figure out a better 68k->PPC translation, you can update the macro definitions, and effectively upgrade LXT, and of course your code that relies on it. It could be a helpful tool if we want to move remaining 68k code to PPC, if anyone is willing to improve the OS 9 Finder and OS 9 System. This could theoretically be done for any existing 68k software of any kind. Kind of like a "caching" of the PPC instructions so that it does not need to go through the 68k emulator (and maybe we could even further customize the output for even better results, potentially). Such an idea reminds me of what is called "ahead-of-time" (AOT) compilation in the context of the likes of .NET and Java.
Checking out Fantasm, and comparing it against both MPW and CodeWarrior, it certainly seems to have its advantages and appeal, but it requires a user/developer that knows assembly or at least C in order to appreciate properly any of those tools. (Being a .NET/Java/etc. guy,
and lazy, and having prioritized other activities, I never got far, so someone else will be a much better judge of all the tooling here.)