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.
Serviio - Web on Big Screen. Serviio enables playback of online sources like RSS feeds, live streams or web site content so that you can listen to your favourite podcasts or watch latest TV programmes published online.
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.
MiniDLNA - MiniDLNA (aka ReadyDLNA) is server software with the aim of being fully compliant with DLNA/UPnP-AV...
iStream - Zero-configuration media-streaming to your SmartTV.