Mighty Networks - Mighty Networks enables entrepreneurs, organizations, and companies to create and grow a community-powered brand.

Attendize Event Ticketing - Attendize is a free & open-source ticket selling and event management platform

Bigtent - BigTent is a web-based organization and communication portal for groups.

Ticket19 - Sell tickets for your events with minimal transaction fees.

Nabble - Nabble is a forum software that are embeddable and fully customizable with scripting language.

pretix - pretix helps you to sell tickets for your event in an easy way. It supports multi-lingual events and provides a wide range of features