https://lispcookbook.github.io/cl-cookbook/

Part tutorial and part recipe site for topics ranging from the common (syntax, the loop macro), to the advanced (packages, multi-threaded web application programming, building stand-alone binaries). It’s extremely thorough in terms of the patterns used in real Lisp code.

I think the most useful aspect is that the recipes go well beyond what’s built-in to Lisp and tackle some of the common (and not-so-common) packages: the chapter on arrays goes into a couple of linear algebra packages, for example. It also has useful chapters on development tasks like profiling and continuous integration.