"Monomarks is an open social bookmarking platform built on the AT Protocol. You can save, organise, and share links to interesting stuff while maintaining full ownership of your data... in the general mould of Pinboard, Delicious"

"LinkStowr is a free, open source and privacy-friendly ... store valuable online resources in a structured and meaningful way". Uses a Chrome extension to save link + note to LinkStowr, and an Obsidian plugin to sync the card to a vault. LinkStowr then deletes its unneeded copy.

A privacy focused extension to annotate, search and organize what you've seen online.