draw.io - Online diagramming application
Festify - Festify is a free Spotify-powered app that lets your guests choose which music should be played...
LucidChart - LucidChart is the missing link in online productivity suites. LucidChart allows users to create, collaborate on, and publish attractive flowcharts and other diagrams from a web browser.
Heartbeat - Listen to music with your friends together, on Spotify
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.
Join My Playlist - Listen to music live together with your friends in Spotify.