TRAVO - Instantly create end-to-end trips around your events.
Attendize Event Ticketing - Attendize is a free & open-source ticket selling and event management platform
Taab - Travel as a benefit™
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Sygic Travel Maps - Itinerary planner for independent travelers
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