Subscription Packages
A lot of streamers that I enjoy watching play together very regularly. Although I can't subscribe to all of them, it would be great if there were an opportunity to subscribe to a group of streamers, with some sort of bulk discount. There are 3 streamers I really enjoy watching, but I only subscribe to one of them due to the price. However, if I could subscribe to all 3 at once for a discount, I would definitely be willing to take that option. Would likely help increase streamer and Twitch revenue as well.
Considering that Twitch already has logic to tell which streamers people "also viewed", this could potentially leverage that logic (or you could allow streamers to create their owns bundles/collaborations).