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Recommendations (for and against) are my personal opinion only and may be out of date.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
Responsive and off-canvas menu (responsive_menu) 2020-11-18

d.o. page

This uses a JS library and works without a second copy of the menu in the HTML, and you don't need to make any changes to your existing navigation menu.

Look at the README file for instructions.
You need to install mm_menu and superfish in your libraries folder.

Note you're forced with the mobile version of the menu to have it expand to full depth (although the hack/workaround, if you want a top-level menu only,  is to hide the lower elements in CSS)

For hand-crated CSS / minimal javascript solutions, see