Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Forekast - Events on Forekast are posted and voted on by the community.
Attendize Event Ticketing - Attendize is a free & open-source ticket selling and event management platform
PodBooker - The easiest way to get booked on podcasts
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
Speaker Directory by HeySummit - Guests for your next event or podcast (or submit yourself!)