The one for reddit is :https://rdx.overdevs.com/ I think nitter was like this too ? Not sure as i have never used it or is just a site to see the posts sent to you ? I think piped works in this same manner for youtube so going to link a client too : https://f-droid.org/packages/com.github.libretube/ . I know barinsta used to be a thing until zuck went after the dev so is there any instagram scrappers now i would love one because then i can actually see what my friends sent me or know what their up to .
Edit: Sorry didn’t read through your post, your title is a bit misleading. I don’t think this will work with instagram or twitter or other related stuff. I still leave my comment in case someone will find it interesting to scrap webpages offline.
Something that works great but isn’t perfect, is to selfhost something like read-it-later (wallabag.
It takes away all the crap and you can even read it later offline with an android (don’t know about ios), and has nice firefox addon.
It’s not perfect because it won’t work for some sites, I encountered some scraping bugs or sites that didn’t work, but most of the time it works great :).
You can even help to make wallabag better.
It’s a very good project regardless. Thanks for reminding me of it. Making a personal, accessible archive of website content is very useful.