Loomio - Loomio helps groups of people make decisions together, online.
Twitter Polls - Polls embedded in tweets
DemocracyOS - DemocracyOS is an open source application for online decision making.
Simple Poll - The easiest way to create polls in Slack
Airesis - A decision making tool for direct democracy and e-government: participate in discussions, bring your ideas, suggest solutions and vote online
Curious Polls - Answer a question once a day for the chance to win £100/$100