Listmonk - Send e-mail campaigns from a powerful dashboard. High performance and features packed into one app.
JOSM - JOSM is a Java-based editor for OpenStreetMap (OSM).
Sendy - Sendy is a self hosted newsletter app that sends emails 100x cheaper via Amazon SES
StreetComplete - Help to improve the OpenStreetMap with StreetComplete!
Mailman - Mailman is free software for managing electronic mail discussion and e-newsletter lists.
Vespucci - Vespucci is the first OpenStreetMap editor for Android.