Reign for Spofity allowed you to control a local Spotify instance from any device on the same local network. It was a free app and the source code is available on GitHub.

The Spotify remote for friends, colleagues, housemates and yourself that works in any browser.

Controlling Spotify from a browser through Reign

Denied app icon

Denied

Skip terrible music

macOS Spotify iTunes Apple Music

Denied saves your ears from Nickelback or any other band, song or album. It sees what you're playing in Spotify and iTunes (including Apple Music) and automatically skips songs that you dislike.

Relax app icon

Relax

Just unplug, no drama

macOS Spotify iTunes Apple Music Free

Relax automatically mutes your internal speakers and pauses music apps when you disconnect headphones.