Universal Media Server - Universal Media Server allows you to host your entire library of video, music, and pictures, and broadcast them conveniently to a wide variety of different devices.
Kodi - Kodi is an award winning free and open source media player that got its start on the Xbox console.
Android TV - Android TV is a version of Android made for TV's
Veso - Veso is an open source media server. An emby/jellyfin fork that will move to a js react framework and focus on remote/rclone mounted media rather than local storage.
PseudoTV - PseudoTV Live is channel-surfing for your media center.
Infuse - Media player and media server with subtitles and wide codec support.