Attendize Event Ticketing - Attendize is a free & open-source ticket selling and event management platform
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Yapp - Yapp enables users to create personalized mobile applications for their events, gatherings, and groups.
Iventlist - Create an app for your event in minutes 🎟️
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
Attendify - Develop relationships at the events that you attend by creating smaller events with just a few people.