Use the same flexible language everywhere: GhPython is the Python interpreter component for GH that allows to execute dynamic scripts.
@it (reads atit) is a free GIS plugin for Grasshopper to parse the geospatial data sets.
Leopard is an open source mesh processing solution for grasshopper.
FractureHopper is an extension of GH for fractal math and chaos theory.
Fast and simple mesh extensions for Grasshopper.
Utilizing MIDI Controllers to drive Grasshopper. Use all those knobs, pads and sliders in MIDI controllers to update your script parameters