vBulletin - Build a community website with the leading forum software, vBulletin 5 Connect, or in the cloud on vB Cloud!
Bloomerang - Bloomerang is a simple donor database and fundraising software solution that helps nonprofits decrease donor attrition and increase revenue.
XenForo - Intuitive. Social. Engaging. Fast. XenForo brings a fresh outlook to forum software.
Kindful - Nonprofit donor database + fundraising tools all in one
Flarum - Flarum is the next-generation forum software that makes online discussion fun. It's simple, fast, and free.
Classy - Expressive, flexible, and powerful stylesheets for native iOS apps