NewPipe, LibreTube, YouTube Media Player, SkyTube, MediaTube, Minitube, VueTube, GTK YouTube Viewer, Gyawun, SongTube, Tubex for YouTube, quietube, SMTube, Echoes Player, iTubeDownloader, YTWatcher, MacTubes, VinnPlayer, QadamSoft Player are some alternatives to Tubbler.