[zerebubuth]

Mapzen, a now sadly defunct mapping startup, released all of its software open-source, including WebGL mobile and browser SDKs, map tile rendering, search and routing. Take a look at:

https://github.com/tangrams/

https://github.com/tilezen/

https://github.com/valhalla/

https://github.com/pelias/

(Full disclosure: used to work at Mapzen)