API List - A collective list of APIs. Build something.
Node.js on App Engine - Fully managed Node.js serverless application platform
Spinneret - Record and Automate Anything on the Web
Dash 4 - Instant offline access to 150+ API documentation sets
PublicAPIs - Explore the largest API directory in the galaxy
The Unsplash API - No-limits, do-what-you-want API for access to 200K+ HD pics.