Twitch Studio - Twitch has released it's own broadcasting software
A streaming app designed for new streamers. Twitch Studio has features that guide you through your stream setup, plus tools that make it easy to engage with your community while you stream.
Twitch Pro from Soundstripe - Create takedown-safe playlists for Twitch streams and VODs
Stream playlists worry-free on your Twitch livestreams and VODs from Soundstripe’s full music collection. Create, shuffle, and access exclusive playlists from lo-fi to EDM for $3.99/month or $36 annually (25% savings).
Twitch Guest Star - Guest Star lets you bring other Twitch users on stream
Through Guest Star, streamers will be able to invite anyone with a Twitch account into a stream from desktop or the Twitch mobile app. Creators can host and manage their guests directly within Twitch Studio or OBS.
Twitch Extensions - Tools that add live apps to live streaming
"Extensions are interactive overlays and panels, developed by 3rd parties, which put you at the heart of the next evolution in live streaming."