OpenBIM addon for Rhino and Grasshopper enabling IFC (Industry Foundation Class) model to be generated and exchanged to ArchiCAD, Revit, Bently, Tekla

Cpython plugin for Grasshopper

Gear is a simple way to generate involute gear This utility is designed 

Pachyderm Acoustic Simulation is a collection of acoustics algorithms which can be used to predict acoustiics and visualize sound propagation.

Free plug-in for Rhinoceros and Grasshopper - parametric 3D multizone building definition - combined thermal and daylight simulation - TRNSYS18

Grevit - Build your BIM Model in Grasshopper. Grevit allows you to create Revit or AutoCad BIM models directly in Grasshopper easily.

Isogeometric Analysis (IGA) - Meshfree FE for Grasshopper

Provide two additional wire type called line wire type, polyline wire type and electric wire type.