Mesh NGon Methods for Grasshopper and Rhino 6 by petras_vestartas: NGon Create, Vertex, Edge, Face Adjacency queries, Subdivide, Planarize, Transform, Utilities. Essentially it is a plug-in for polygonal meshes.

Making use of Grasshopper uto developed an interface named GECO, which offers a direct link between Rhino/Grasshopper models and Ecotect. The Plugin allows you to export complex geometries very quickly and evaluate your design in Ecotect.

Crystallon by aporterfield is an open source project for creating lattice structures using Rhino and Grasshopper3D. Each tool is left as a cluster which can be opened and modified at will, in the spirit of open source.

Fox by petras_vestartas includes series of algorithms for Graphs, Aggregations, Iso-surfaces. It was developed for Aggregation and Graph-Based Modelling Workshop at Vilnius Academy of Arts (VAA).

Panther by Panther Technologies combines the most versatile Jewelry Builders with an Interactive Gallery bringing premeditated parts to go into construction of a complete final piece.

4D Noise component by giulio@mcneel.com creates Perlin and Simplex noise. This add-on forms smooth 4D Perlin noise and Simlex noise, two very well-known smooth noise functions investigated by Ken Perlin.

Parakeet by Esmaeil is a collection of components focusing in Algorithmic Pattern Generation; it offers a Unique and easy-to-use approach that Generates Geometrical and Natural Patterns/Networks.

Wallacei (which includes Wallacei Analytics and Wallacei X) is an evolutionary multi-objective optimization engine that allows users to run evolutionary simulations in Grasshopper 3D.

Pufferfish by ekimroyrp is a set of 305 components which focuses on Tweens, Blends, Morphs, Averages, Transformations, & Interpolations. Pufferfish mainly uses parameters and factors for inputs for more custom control over operations like tweens.

Dendro by ryein is a volumetric modeling plug-in for Grasshopper built on top of the OpenVDB library. It provides multiple ways to wrap points, curves, and meshes as a volumetric data type.

Conduit is an open source plug-in authored by Proving Ground. Conduit enables designers to create custom data visualizations and heads up displays that update with your parametric models.