Advanced Custom Fields (ACF): https://wordpress.org/plugins/advanced-custom-fields/
SSL: https://wordpress.org/plugins/really-simple-ssl/
Cookie Notice (GDPR) by dFactory: https://wordpress.org/plugins/cookie-notice/
Menu icons by ThemeIsle: https://wordpress.org/plugins/menu-icons/
Menu item visibility: https://wordpress.org/plugins/if-menu/
Widget visibility: https://wordpress.org/plugins/widget-options/
Tips and Tricks
File permissions in wordpress: https://stackoverflow.com/questions/18352682/correct-file-permissions-f…
Speed and Optimization
https://onlinemediamasters.com/wordpress-speed-optimization-plugins/
https://bloggingwizard.com/free-speed-enhancing-wordpress-plugins/