"QuantEcon:Open source code for economic modeling"
https://quantecon.org/ has Python and Julia versions. The Federal Reserve uses Julia in its macroeconomic models:
https://frbny-dsge.github.io/DSGE.jl/latest/ . Some economists use Fortran (which is much modernized since FORTRAN 77), and there is a 2018 book Introduction to Computational Economics using Fortran
https://www.ce-fortran.com/ . Some Fortran codes in economics, statistics, and time series analysis are listed at
https://github.com/Beliavsky/Fortran-code-on-GitHub .