Dynamic 3D Sectioning and 2D Layouts for Rhino Helps create sections that update with model changes.  Sections can create outline curves,

Ecotect is a highly visual software for architects to work with environmental performance issues. It is designed for early stages of conceptual design

Firefly offers a set of software tools dedicated to bridging the gap between Grasshopper (a free plug-in for Rhino) and micro-controllers like the Ard

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

New version for rhino 5 here Auxpecker is an easy and free solution to get a pleasing realtime preview of objects directly on the viewport of Rhino

Karamba3d is a parametric structural engineering tool which provides accurate analysis of spatial trusses, frames and shells.

EvoluteTools LITE for Rhino 5 and 6 is a free Rhino plugin allowing intuitive design of panelizations using subdivision modeling and mesh optimization

KUKA|prc enables you to program and simulate industrial robots directly out of a parametric modelling environment.