Yoast - Yoast offers plugins to improve SEO and optimize web sites and blogs.
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
WP Rocket - WP Rocket offers a caching plugin for Wordpress.
Live Chat by Sumo.com - Instantly communicate with customers, prospects & visitors
Wordfence - Comprehensive security plugin for WordPress.
Drift - A messaging app that helps you grow your business.