Online-RSVP.com - Beautiful online RSVP for wedding & other events. Create an online invitation, track your guests responses.
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
RSVPify - A powerful and awesomely customizable platform for selling tickets online for your event.
Ticket Tribe - Sell tickets online with no fees per ticket
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
Meetinch Attend - Your personal RSVP tracking assistant