Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Attendize Event Ticketing - Attendize is a free & open-source ticket selling and event management platform
TicketSource - Free, easy to use online ticketing for your events.
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
Bookitbee - Bookitbee permits event coordinators to set-up an event and offers tickets online in minutes.
Ticket Tribe - Sell tickets online with no fees per ticket