There are too many to list here, but I used the W3C link checker to check the links in the "Important links" chapter (https://koha-community.org/manual/latest/en/html/links.html) We should remove the ones that don't work anymore. Is this page useful at all? Link check report (it takes a few minutes): https://validator.w3.org/checklink?uri=https%3A%2F%2Fkoha-community.org%2Fmanual%2Flatest%2Fen%2Fhtml%2Flinks.html&hide_type=all&depth=&check=Check
I never noticed this page /chapter before (!) So I totally agree with the "is it useful" question. I'd expect all the Koha links are already elsewhere in the Manual, in the relevant contextual sections. External services probably don't need to be listed. The links to other resources about Koha should be added to the new "other resources" page (see bug 38260). To summarise: I'd vote for taking down this page.
I tidied up the page and fixed the links in Bug 41498 - Documentation maintenance tasks - December 2025. At the time, I didn't think about removing it. I'll remove the page after addressing Bug 38260 - [DOCS] Add a community resources page to the manual (or maybe repurpose it for that to minimise broken links).