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

attending.io - Tiny event pages to ask people one question – are you attending? Twitter login.

Eventzilla - Eventzilla lets you sell tickets online and manage attendees from one integrated application.

Ticket Tribe - Sell tickets online with no fees per ticket

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