Not really. I didn't find a comprehensive one. I got most of what I needed from looking at other plugins. I did look at https://github.com/Pepitu/Moodle-specific-TinyMCE-example-plugin, but I suspect you're well past that basic level point. I basically used it to get a feel for how other plugins work.
I've been able to successfully build my plugin using a tinymce plugin and a local plugin. The local plugin does the work of retrieving the LTI information and signing the request URLs and the tinymce plugin uses the signed urls to retrieve the data and display it to a user.
The mediacore plugin linked above does that (and more), with the crucial logic being in the client class. It also shows you how to setup settings for a local plugin, if you didn't know.