Attendize Event Ticketing - Attendize is a free & open-source ticket selling and event management platform
SkillMint - Find, meet and rate people with common skills and interests. Community-driven rating system.
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
ACTIVE JumpForward - JumpForward serves over 150,000 users and 175 college athletic departments with recruiting and camp management software built to keep you compliant.
Ticket19 - Sell tickets for your events with minimal transaction fees.
Guestboard - Lead powerfully-organized group events with Guestboard – a modular event platform that gives groups of 10-1000+ people a central space to coordinate, build excitement, and save money. No more crazy email threads. No more massive group texts.