An Understrap child theme (based on the starter child theme) for my personal Superman-themed blog Small Screen Superman. Most of my work is found in the src folder and in functions.php.
Note that Small Screen Superman also has non-WordPress content, and that the SASS references some files that are contained outside of the WordPress files. Thus, if you try to use this theme yourself, a few things (such as images and fonts) won't work. I mainly have it on GitHub for reference rather than for this theme to be used by others, but if you are interested in this theme and would like help with making it work, feel free to contact me.