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.
Twitter Polls - Polls embedded in tweets
Airesis - A decision making tool for direct democracy and e-government: participate in discussions, bring your ideas, suggest solutions and vote online
Polls for WhatsApp - Create & share quick polls in your WhatsApp groups