Between a wiki page and a wikified forum post, I think a wiki page is better.
But, script authors have only little time to document scripts.
We only write a quick description in the script itself like you can see in this automatic list of userscripts that can run on MB sites.
Yes, I am showing you yet some other places with lots of MB scripts and I agree we should try to have one official place or something.
Such a list is cool but authors have to upload their scripts once on greasy fork (it will then auto update from author’s git repositories each time version goes up).
I am afraid that any other kind of more complete documentation might end up obsolete quickly.
User scripts themselves can already get obsolete quickly.
We also have an OUJS MB group but this kind of tag is worse than previous list as author had to both upload script on OUJS and then to tag their script as being MB.
We also have a New MusicBrainz userscripts topic and a userscripts tag, here.
When userscripts.org was still there, everybody seemed pleased with their then musicbrainz tag so maybe previously mentioned Greasy Fork’s list or Open User JS’s tag would be ok if all authors would at least upload there?
But another problem is that we may have list with many obsolete or even abandoned scripts so a wiki may still be better to avoid that.
All ideas I have read are good.
Also with Greasy Fork versioned library system, it is possible to share libraries between scripts in distinct repositories (for example if a script uses this or that version of a library, it will keep pointing to that specific tested version even if the library later completely changes).
Indeed me and @loujin had such a shared library for loading MB entities in mind but I had no free time yet.