you’re welcome @tmcmillan99, I hope it’s helpful!
Part of the push with the boilerplate is likely due to making the barrier to entry for devs new to HubSpot easier and also probably something to do with getting approval for marketplace themes.
Have you already taken the CMS for Developers certification? I built a bare bones theme from scratch (no boilerplate) and had far fewer files than what the boilerplate has.
Teun mentioned the layouts.css, in mine I didn’t break that out into a separate file and had all of my CSS in a single theme file, but it did make me realize that you’d also need the layouts folder and base.html file as part of your minimum. And then depending on how you build your header/footer, you’d need the partials.
Here are the files from my certification theme:
Obviously things like section templates and modules would be optional, otherwise I feel like this is pretty close to the minimum.
There are a lot of themes that breakout the CSS and JS for every module (instead of using it within the module code), which allows the performance to improve (the code is only loaded once per page instead of for each module). Using macros is also a huge advantage for performance, but adds to the total number of files.