WP Rocket - WP Rocket offers a caching plugin for Wordpress.
Bloomerang - Bloomerang is a simple donor database and fundraising software solution that helps nonprofits decrease donor attrition and increase revenue.
Yoast - Yoast offers plugins to improve SEO and optimize web sites and blogs.
Kindful - Nonprofit donor database + fundraising tools all in one
Wordfence - Comprehensive security plugin for WordPress.
Classy - Expressive, flexible, and powerful stylesheets for native iOS apps