We have published our Datagrok UIKit for rapid prototyping on Figma Community: https://www.figma.com/@datagrok. Duplicate the Figma file and use it for your own design prototypes.
Datagrok Figma UIKit is based on Datagrok JS API. It contains all the necessary elements and components which could be useful in your future prototypes. Each component contains a link to the documentation which helps you implement your prototype in Datagrok. https://github.com/datagrok-ai/public/blob/master/help/develop/ui.md