Gnomecast allows you to cast media from your Linux machine to your Chromecast.
BUTT makes streaming media much easier and possible on all three major desktop operating systems.
Radio Tray Lite lets you play online radio with minimum options and interface on your Linux machine.
Periscope allows you to broadcast live video and see others’ live streamings on your devices.
WebTorrent Desktop app lets you directly stream media content from the torrents without downloading them.
BubbleUPnP lets you stream media to various devices and lets you choose the source of media from a number of options on your device.