Armadillo is a plugin based on parametric arrays along path curves. It can create wide range of solutions

Auxpecker Studio is an easy and free solution to get a pleasing realtime preview of objects directly on the viewport of Rhino3D

Create accurate Metric and English Bolts and Nuts in Rhinoceros

BrickDesign enables the controlled design and manipulation of a large amount of discrete elements.  The plug-in provides a parametric design en

Bubble for Rhino is a free tool from Asuni CAD that displays a tooltip with information of any object in the document.

BullAnt is a Rhino3d/Grasshopper plug-in primarily for Architects and Engineers (but also other Rhino/Grasshopper users) featuring computational

Clayoo is a 3D freeform and organic modeling plugin with three technologies in one (SubD, Emboss and Sculpt) and 100% compatible with Grasshopper.

Clipper for Grasshopper and Rhino Clipper is a 2D polygon Clipper offering polygon boolean operations (clipping): Intersection, Join, Difference, X