Google Groups - Google Groups allows you to create and participate in online forums and email-based groups with a rich experience for community conversations.
Agilon One - Agilon One is a Nonprofit CRM software solution that connects and gathers information on constituents.
Membee - Membee is web-based membership management software.
Classy - Expressive, flexible, and powerful stylesheets for native iOS apps
Galette - Galette is a membership management web application towards non profit organizations.
Little Green Light - Illuminating Data. Advancing Nonprofits.