Extravaganza - Airbnb for live entertainment!
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Seatify - Reserve a seat at cafe & office from people there
Attendize Event Ticketing - Attendize is a free & open-source ticket selling and event management platform
Guestlist - Market events online, accepting registrations & ticket sales
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