No WWDC app for OS X videos yet. You could help us improve this page by suggesting one.
Plex for Alexa - Run your home theater or play your favorite playlists
WWDC Together - Watch and discuss WWDC together
Mi Box - 4K Ultra HD streaming and gaming box powered by Android TV
WWDC TV - Watch WWDC video on your Apple TV
BitTorrent Live - Live streaming video. iPhone, Apple TV, MacOS. Android soon.
NotesKey - Time travel through Apple's keynotes