Kangaroo is a Live Physics engine for interactive simulation, form-finding, optimisation and constraint solving.

Open-source combinatorial toolkit for discrete design. Offers tools to quickly generate geometry- and data-driven aggregations of generic parts.

Box2D is a 2D rigid body simulation tool for Grasshopper. It uses Box2D physics engine and a C# wrapper from colgreen/box2Dx. 

Welcome to Human for Grasshopper! Human extends Grasshopper's ability to create and reference geometry including lights, blocks, and text objects.

Ivy is a Grasshopper add-on for mesh segmentation and fabrication.

A design tool for typology-oriented building massing design generation, optimization, and exploration

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

Series of algorithms for: a) Graphs b) Aggregations c) Iso Meshes