The one you linked is a pretty typical relational model and isn't bad, but it has trade offs that I'd personally not make, however, that doesn't make it bad.
In the end context, scale and usage all determine a good schema design. Sometimes what would be a good relational design on paper would be tragically horrid in practice once you get beyond a small dataset.
That said, some of the best things to look at are open source projects and research their pain points and highlights. That will many times point you to the tradeoffs they made in modeling and in code. For e-commerce things like magento and other open source solutions can be really informative, even woocommerce and how it shoehorns itself into wordpress can be informative as to the tradeoffs on highly normalized vs lightly normalized vs key/values etc.