Attendize Event Ticketing - Attendize is a free & open-source ticket selling and event management platform
Send Me Color! - With Send Me Color! you can send a hint to your contacts that will look like color card.
Ticket19 - Sell tickets for your events with minimal transaction fees.
Partey.io - Invite to parties and events. Dead simple, privacy-first. Just send a link to your friends. No accounts needed!
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
1up Events - Corporate events as a service