Typesense - Typo tolerant, delightfully simple, open source search 🔍
Search Later - Save interesting article keywords to Google them later 🤓
Expertrec - Adds super fast search autocomplete, spell correct and search listing pages to your site search.
Newsit - Find the discussion around the page you're looking at!
Appbase.io - Search stack for building modern apps
Six Degrees of Wikipedia - Find the shortest path between two subjects