Here is a list of plugins that I consider Go To Plugins that I trust and use on a regular basis when I need to add a new feature to WordPress Websites.
Feel free to expand the list with plugins that you recommend that are published on WordPress.org
Development and Operations
Convenient for making newsletters, particularly when they need to be sent automatically after content is published.
Email sending server so your emails don’t get blocked by spam filters.
General good security plugin
Security using White List and Black List of IPS
Strict IP whitelist, only whitelist IP has access to Admin area