Most of the information on this page is taken from the website of Christoph Kronenberg who I thank you for putting together such an useful list of resources.
Econometrics
Free text books on econometric methods with focus on causal inference
Free video resources on econometric methods with a causal inference focus
Free coding resources
Mostly Harmless Econometricsin Stata, R, Python and Julia.
Other useful links
Academic citizenship
Academic writing