I have two books currently in production. Both are open-access and open-source. The first is a principles of microeconomics book and the second is a book on the economics of the environment. Both are written in markdown and converted to html, pdf, epubs, etc. using quarto. The html files are then hosted on github pages.

Open Principles of Microeconomics

Can be accessed at Open Principles of Microeconomics

Earth-Economy Modeling

Not yet public, but soon will be hosted here. This is a book about the GTAP-InVEST model and the related set of similar models and tools.