Twitter Polls - Polls embedded in tweets
Loomio - Loomio helps groups of people make decisions together, online.
Simple Poll - The easiest way to create polls in Slack
DemocracyOS - DemocracyOS is an open source application for online decision making.
Polls API - Scalable, efficient API to build polls, quizzes, ratings and many more
Airesis - A decision making tool for direct democracy and e-government: participate in discussions, bring your ideas, suggest solutions and vote online