@rheedi0 wrote this post on building a media store https://medium.com/@rheedio/a-crash-course-in-lightning-app-development-part-deux-51a8e48a4540

This guide https://docs.lightning.engineering/ by LL is also quite good.

There are probably others. But to be fair Lightning apps have maybe been decently easy to build for a little over a year so there aren’t many write ups yet. We definitly need more