I had an idea for a handy Grasshopper widget set: Unit conversion, such as length, mass, volume, etc. Perhaps there could be a widget for each class of conversion, using two dropdowns inside the component.
There would be an input and output connection/wire.
The legend on the component would reflect the class of conversion. The user could see that:
“Foot → Milimeter”
“Kilo-pascal → Bar”
Showing that Inches to Millimeters might be more meaningful than seeing a widget group multiplying a number by 25.4.
The idea is a natural extension of the Radian and Degree conversion components.