Vacuum Data - Instant access to all* open data from a single place
Mocklets - A HTTP-based API simulator to assist parallel development 🛠️
Mapsense - The API for data-driven mapping
API List - A collective list of APIs. Build something.
OpenStreetMap - OpenStreetMap is a map of the world, created by people like you and free to use under an open license.
TweetEraser - I'm trying to make your Twitter life a bit more easier.