Dashblock - Turn any website into an API
PublicAPIs - Explore the largest API directory in the galaxy
Sheety - Turn any Google sheet into an API instantly, for free. Power websites, apps, or whatever you like, all from a spreadsheet. Changes to your spreadsheet update your API in realtime. Neat
API List - A collective list of APIs. Build something.
Postman - The Collaboration Platform for API Development
API for Product Managers - The A to Z of APIs for product managers