vsc-plus by Blackphi6

Video Speed Controller Plus controls HTML5 video and audio playback speed with keyboard shortcuts and an optional on-screen controller. It is a fork of Video Speed Controller with extra customization and localization.

Core features
- Speed up, slow down, rewind, and advance with customizable shortcuts
- On-screen controller overlay for HTML5 video and audio
- Frame stepping and time seek shortcuts
- Optional playback-speed memory and per-site rules
- English, Japanese, and Simplified Chinese UI

Plus extras
- Customize controller colors, opacity, border, button size, and font weight/width
- Live appearance preview in Options
- Light, dark, and system UI themes with accent colors

Works on most sites using standard HTML5 media. Google Meet and Hangouts are excluded by default.

Open source: https://github.com/Blackphi6/video-speed-controller-plus