The Unsplash API - No-limits, do-what-you-want API for access to 200K+ HD pics.
Lasso Content Curation - Become an information ninja. Stop losing the info you need.
PublicAPIs - Explore the largest API directory in the galaxy
Pocket - When you find something you want to view later, put it in Pocket.
API List - A collective list of APIs. Build something.
Pinboard - Pinboard is a personal archive for things you find online and don't want to forget.