Forum user luni couldn’t find a stepper motor library to meet his needs, so he wrote his own. The library is able to handle up to 300,000 steps per second.
This video shows two steppers running up to 160,000 steps/sec.
There is a great write up and explanation on luni’s GetHub Page. The page includes excellent explanations and diagrams on the three types of movements.
The library handles the three different movement modes when controlling more than one motor – Sequential Movement, Synchronous Movement, and Independent Movement.
Luni published performance metrics running 1 and 3 motors on 2 different boards.