Ladybug and Honeybee are open source environmental plugins for Grasshopper to help designers create an environmentally-conscious architecture

Provides components for building structural models to be analysed in Consteel, and two-way connection between Grasshopper and Consteel.

Peregrine is a powerful structural layout optimization tool with a host of powerful editing and rationalization functions.

Volumetric Modelling components for Grasshopper.

Pterodactyl is an open-source plug-in for the purpose of generating custom documents, reports, articles, etc. that can be updated in real time.

A quick and dirty workflow to keep default values in your definitions

Opossum offers some of the best performing optimization algorithms in Grasshopper: model-based RBFOpt and RBFMOpt and evolutionary CMA-ES and NSGA-II.

Groundhog is a Grasshopper plugin and wiki exploring the applications of computational design in landscape architecture.