Nightler - Find the people. Live the night.
Attendize Event Ticketing - Attendize is a free & open-source ticket selling and event management platform
Party with a Local - Party with a Local is a free app that connects travelers with locals that want to party.
Ticket19 - Sell tickets for your events with minimal transaction fees.
Discotech - Opentable for nightlife. Tickets, guest lists, and VIP.
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