Jim Fowler, Bart Snapp, and I collaborated on a project called "Mooculus".
The main page is here: https://mooculus.osu.edu/
There is a free open source textbook (mostly Bart), youtube "lecture" videos (mostly Jim), and Khan Academy style practice exercises (mostly me).
Here are some highlights from the interactive stuff. Note that you have to log in with a google account for any of this to work unfortunately.
This let's a student enter any elementary function, and we algorithmically compute the derivative step by step, while citing the appropriate derivative rule.
Forces the student to graph a tangent line to a function
Gives student access to a "black box" function, and asks them to approximate the derivative
There are many more for you to explore on the webpage. For instance, chain rule problems with tables, problems where they have to differentiate an arbitrary elementary function (we have an expression input), problems that force them to think about derivatives of inverse functions geometrically, etc. We have not done much maintenance, so there may be some bugs (I think, sadly, a mathjax update killed some of our multiple choice questions, for instance).