Keyspider.io - Keyspider is a cloud-based search platform that provides the best search experiences for users across your Websites, Ecommerce, Services, and Workplace.
Yoast - Yoast offers plugins to improve SEO and optimize web sites and blogs.
ElasticSearch - Elasticsearch is an open source, distributed, RESTful search engine.
Wordfence - Comprehensive security plugin for WordPress.
Algolia Search for WordPress - Bring instant and relevant search to your WordPress blog
Jackmail - A newsletter plugin for Wordpress.