Welcome! There are a number of notebooks and algorithms here on the site both in the Tutorials and the Lectures. These can be found under the 'Learn' tab in the top menu bar of each Q page. I agree that working with existing code is a great way to learn. The lecture on Universe Selection may be a good one to start with. It not only shows a lot of the code but also details the importance of narrowing ones algo to a defined universe. The forums here are also a good source of sample notebooks and algos though less structured.
There may be some notebooks and algos on the web other than those here on the site? It would be good to hear if there is.
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