Readwise - Effortlessly rediscover and organize your Kindle highlights
Clippings.io - Organize the notes you make on your Kindle
Tressel.xyz - Save content from the Internet (like Twitter & Reddit) and export it to Notion, Obsidian & Evernote
Newsletters to Kindle - Read your newsletters on your Kindle
Wellput - Export your Kindle highlights into a personalized library
Nimbooks - Host all your digital reads in one place