I made a Python library for simulating the combined effect of recurring events over time. E.g. financial events like salary, inflation, costs, etc. Has quite a lot of powerful stuff for analysis as well, and it made me use excel even less, which is the main reason I like it :)
You can find it at: https://github.com/TimoKats/pylan, I've also made a slidedeck which is available here: https://timokats.xyz/downloads/2025_pylan_presentation.pdf