FfsubsyncAutomagically synchronize subtitles with video.
nekocapBrowser extension for creating & uploading community captions for YouTube, niconico and other video sharing sites.
youtube-vtt▶️ Extract and save WebVTT closed caption tracks from YouTube videos
ccaptionerAn extension to assign a text track to a video element in a web page
electron-video-downloaderA minimal Electron application to download videos, eg from youtube, and associated captions (optional). Uses youtube-dl under the hood.