Here are a few resources I've discovered online that contain useful information: https://www.cfinotebook.net https://www.thecfiguy.com (full disclosure: I did my commercial multi add-on with Domenic and he's a phenomenal CFI) http://www.code7700.com Also, anything from Rod Machado is always helpful (and usually humorous) as well: https://rodmachado.com/blogs/learning-to-fly/tagged/cfi-resource-center