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
Owlie - A beautiful app for quick decision making with friends
Surveys in Slack by Polly - The world's first fully immersive Slack-based survey product
Decidim - Free Open-Source participatory democracy for cities and organizations