wxWidgets - wxWidgets: Cross-Platform GUI Library
Google App Engine - A powerful platform to build web and mobile apps that scale automatically.
Electron - Build cross platform desktop apps with web technologies
Dokku - Docker powered mini-Heroku in around 100 lines of Bash
GTK - GTK+ is a multi-platform toolkit for creating graphical user interfaces.
Google Cloud Functions - A serverless platform for building event-based microservices.