The venerable youtube-dl. (supported sites)

Always try this first, then look around for alternatives.

Make sure you're up to date though! youtube-dl -U

Analoguous to youtube-dl, there's gallery-dl (supported sites)

For all zoomable images (Google Arts & Culture, hi-res scans, etc.): https://dezoomify.ophir.dev/dezoomify/dezoomify.html (also has a standalone version)

• https://addons.mozilla.org/en-US/firefox/addon/hls-stream-detector/
• https://www.downloadhelper.net/
• https://www.downthemall.org/