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Recommendations (for and against) are my personal opinion only and may be out of date.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? I will be adding this, but as of August 2021, this site you are reading is the only Drupal site of mine I've been able to upgrade to D9, so although you can check D9 compatibility status of all modules (use upgrade_status, it's superb) I can't speak from personal experience about any of them.

(1 modules in list)
Module name or machine name
Any text in the notes
Name D8 Personally Tested Last Updated
Role Delegation (role_delegation) 2018-11-20

d.o. page

Ordinarily, if you grant a user "Administer Users", they can do everything *except* change the roles (they don't even see the checkboxes).  You could give them 'Administer Permissions', but that also allows them to do other things.  

This module lets you set which roles they are allowed to enable for a user.  Administrators still see the roles checkboxes in the usual place (below 'status' on /user/123/edit), but everyone  gets a new 'Roles' tab.  

Works with D8 but not updated since April 2016.

Patches:

I'm not using any patches, but there are a couple RTBC-ed  the queue.