Following Filters for Twitch от Adam

Adds a filter bar to your Twitch "Following — Live" page.

Hide mode removes channels matching your filters.
Show mode displays only the channels that match.
Filters match game titles, channel names, and stream titles.
Typing suggests games from the channels currently on the page.
Your filters are saved and reapplied on your next visit.
Add a filter with Enter or the ✓ button, click a filter to remove it, or use the trash button to clear them all.

The "Overview" tab of the Following page redirects to "Live", where the filter bar lives.