Useful Drupal modules

Click on the module name for notes, comments, patches.
Recommendations (for and against) are my personal opinion only and may be out of date. Feel free to email with corrections/suggestions.

Why haven't you mentioned Drupal 9? As of December 2021 I've updated most of the sites I look after to Drupal 9 (experience: mixed). I haven't decided how to label future version compatibility as D10 will be coming soon as well. The upgrade_status module is superb. You're bound to have issues with composer. Also watch out for a nasty session headers bug with redirect_after_login.

(1 modules in list)
Module name or machine name
Any text in the notes
Name D8 Personally Tested Last Updated
AJAX Comments (ajax_comments) 2018-11-23

d.o. page

Not recommended

Not very actively maintained and it can be quite buggy.

Needs this patch:

Reply button can be pressed multiple times, resulting in multiple comment forms

I abandoned it for a project because the admin XHR response when you submit comments sends back comments you've already filtered out (I had written code to restrict visibility of certain comments).   Also had a problem where the initial comment form was left in place rather than being replaced, so you ended up with duplicates.