[dvas]

Lots of other great answers, another one I came across recently is FinGPT[0]. For backtesting there is zipline [1], but doesn't look like it's maintained anymore.

[0] FinGPT: Open-Source Financial Large Language Models https://github.com/AI4Finance-Foundation/FinGPT

[1] Zipline is a Pythonic algorithmic trading library https://github.com/quantopian/zipline

[claytonjy]

another comment in here mentioned Zipline Reloaded¹, a fork from a guy who wrote a book using Zipline. Last commit 6 months ago, much better than 3 years from the original.

¹: https://github.com/stefan-jansen/zipline-reloaded