Most of mine was just automation or analysis-download mp3 rips from a streaming site, scrape parse and analyse jobs so I could see the market prices (span off a web app made a few hundred quid but killed it), a trading system and crypto analysis tool, most recently scraping and analysing housing market data.
Try Trading Systems by Tomasini and Stocks on the move by Clenow, Python for finance. For the code side there's not much ultimately you have to build it yourself and learn.
They were fairly simple, using simple maths or technical indicators, or simple pandas calculations depending on the system. They all generally were based on the momentum behaviour of markets.
The hard part is the backtesting and design of strategies talking into account the science and art of it. And the absolute truth that past performance does not dictate future results.
I haven't tried non-crypto, I think I will just leave that to simple investments in tracker funds or etfs.
Not sure why a simple book review has so many upvotes.
A couple years ago I read all I could on this and started systematic trading on crypto. Ended up with the best results on a public platform and ran a small trading operation with a few clients, one a crypto market maker. It's really hard due to all the market unknowns, stress and psychology/emotion. After the FTX debacle I lost ~35% of capital. Currently put it on pause and back software engineering.
Had to rebuild my asset allocation system which was based on FTX api. Improved it to be realtime and using Binance api. There's still the counter party risk-Binance could get busted or USDT fraud.