Also Pyre [0] by Facebook and Pytype [1] by Google. More importantly, the core part (type annotations) allowing these libraries to exist has been added to core python for years now and keeps on evolving, so it is an ongoing effort.

EDIT: As mentioned below, also added Pyright [2] by Microsoft

[0] https://github.com/facebook/pyre-check

[1] https://github.com/google/pytype

[2] https://github.com/microsoft/pyright