RSVPify - A powerful and awesomely customizable platform for selling tickets online for your event.
Twitter Polls - Polls embedded in tweets
Punchbowl - A party planning and greeting card website
Simple Poll - The easiest way to create polls in Slack
Whoozin.com - Free RSVP Online | Track RSVP’s and Sell Tickets for your events and recurring meetings.
Polls API - Scalable, efficient API to build polls, quizzes, ratings and many more