http://www.math.wisc.edu/talent/

Calc3D Plot:

http://web.monroecc.edu/manila/webfiles/pseeburger/CalcPlot3D/

https://sites.monroecc.edu/multivariablecalculus/

overview: https://www.maa.org/press/periodicals/loci/resources/calcplot3d-an-exploration-environment-for-multivariable-calculus-overview

Project page: http://web.monroecc.edu/calcNSF/