Videolyzer от LoreRuff

One timeline for the whole playlist.
Cross-video seeking, hover previews straight from YouTube's own storyboards,
a queue that stays live while you watch.

YouTube resets its progress bar at every video boundary. Videolyzer draws one
bar over the player covering the entire playlist or queue: two content
scripts, one event channel, zero permissions.

• One continuous timeline — every queue video becomes a segment of a
  single bar, with ticks at boundaries and a live position across the whole
  queue
• Cross-video seeking — click, drag or arrow-key anywhere, including
  inside videos you haven't reached yet
• Hover previews — real storyboard frames on the playing video, cover
  thumbnails for every other segment, title and absolute queue time always
  visible
• A queue that stays live — add or remove videos while watching and the
  bar grows in real time, refereed against the player's own live queue order
• Keyboard first-class — ←/→ for small steps, Shift for big steps; the
  bar is an accessible ARIA slider
• Honest guards — ads freeze the timeline, shuffle disables scrubbing,
  live streams bow out