Fider : Fider is an open platform to collect and organize customer feedback. By using the platform, your community can share, vote and discuss on ideas they h...
SimpleLogin : With email aliases , you can be anonymous online and protect your inbox against spams and phishing. Open-source.
Astuto : Astuto is a free, open source, self-hosted customer feedback tool. It helps you collect, manage and prioritize feedback from your users.
Mattermost : Mattermost is a self-hosted solution for bringing all your team communication to one place, and making it searchable and accessible anywhere
Lemmy is a selfhosted social link aggregation and discussion platform. It is completely free and open, and not controlled by any company. This means that there is no advertising, tracking, or secret algorithms.