osm2pgsql
OpenStreetMap data to PostgreSQL/PostGIS converter
BlueMap
BlueMap is a Minecraft mapping tool that creates 3D models of your Minecraft worlds and displays them in a web viewer.
Fatiando a Terra
Open-source Python tools for geophysics
OpenLayers
Transportr app
JOSM Open Street Map
Caglow
A movement to bring free and open astronomy down to Earth.
Organic Maps
Fast detailed offline maps, based on OpenStreetMap and curated with love by MapsWithMe founders.