SnappingGecko is a free Grasshopper plugin which provides object snapping features, helping you to keep your definitions clean.

Parallel High-Performance Components for Grasshopper

Flatworm is a python module and GHPython implementation for generating rigidly foldable quadrilateral meshes (RFQM) in Grasshopper.

A collection of useful tools (some more some less so). I will be updating this as I continue to add new components.

Chimpanzee plug-in is suitable for fractal enthusiasts.

PhysX.GH is a rigid body simulation tool for Grasshopper, using open source real-time physics engine NVIDIA PhysX.

Githopper is a powerful open-source Git interface for grasshopper that makes working with Git both safe and beginner-friendly.

Center of mass calculation for multiple objects of varying density.