My greatest advice to those concerned: Start archiving. If you come across something you believe is valuable: make a copy.
If you follow a guide on how to install and configure software and you found it helpful: make a copy.
If you come across a video you really enjoy and find yourself coming back to again and again: make a copy.
If it means anything to you: make a copy, or you'll wish you did.
@rick While I do not have a list readily available, I can provide some ideas.
For images, use right-click > save. If the website blocks right-click, then you can inspect element and find the image in the page source.
For text/static webpages, use right-click > save page as. Copy/paste works well for strictly text stuff.
Keep it simple: If you're archiving something, then store it in a widely supported and accessible format.
(1/2)
@rick For videos, use yt-dlp[1]. There is a GUI frontend available for it which should help make it more user friendly[2].
[1] https://github.com/yt-dlp/yt-dlp
[2] https://github.com/ErrorFlynn/ytdlp-interface
(2/2)