The only alternative I know of is Memex. It’s open-source, works offline and has cross-device synchronization. As I don’t use bookmarks all that much myself, I’ll leave you to decide if this works for you better than raindrop.
I use turtl
I heard Wallabag can do this, but I’ve never personally used it. I think this is more like a pocket alternative more than syncing bookmarks.
I hope this helps.
I use Raindrop because I think it’s a great service but I’m thinking about changing too.
Unfortunately, Memex backup/export is way too big, my current 802KB html file when imported to Memex creates backup files totalling 80MB, pretty inconvenient to me.
Turtl seems like a great option too, but I can’t seem to import any html file to it.
I use Wallabag for pages I want to read later (it is pocket replacement)
For bookmarks, I use floccus extension and Nextloud bookmarks app. It sync great across mutliple browsers and systems (Android app doesn’t sync folder structure, only pages, though for phone I prefer Wallabag). Good thing is - all bookmarks are available via Nextcloud web, in case you’re using some other PC
I use https://xbrowsersync.org (and decided to run a public server for) which has addons for most browsers and an Android app.
The bookmarks are encrypted before upload.
Yeah, I like raindrop and I’m trying to switch to turtl, the problem really is that I can’t import my bookmarks to it.
This is the best that there is, but it is not finished and the main developer doesn’t have time to finish it currently, but maybe if you all could spread the voice they could get more people to help and make it happen since it looks like an awesome project with a really good aesthetics, also.