BitTorrent Live - Live streaming video. iPhone, Apple TV, MacOS. Android soon.
WWDC Together - Watch and discuss WWDC together
IINA - The modern video player for macOS
WWDC app for OS X - An app to view and watch WWDC sessions on your Mac
VLC Media Player - VLC is a free and open source cross-platform multimedia player and framework.
Plex for Alexa - Run your home theater or play your favorite playlists