Poll: What makes this set so special (April 2019)? (Patreon)

This set is my most popular set, ever. By far.

• It's sold 4 times more than most of my other art packs on Gumroad,
• that month (April 2019) was the largest growth of patrons I have ever experienced, nearly doubling the second best month to date.

But I don't know why it's so much more popular than the rest of my work! 

If I could figure out the essence of it, I could apply that knowledge to my work, going forward. of course, as an artist supporting himself with his work, it's lucrative nature is important to me. But even more interesting to me is the "why". I want to tap into that, so I can concentrate it into new works, with intent instead of accident, to make even better art going forward.

I recently posted this question on Twitter:

 https://twitter.com/RoninDudeArt/status/1278495839774597120 

And I received some good reasoning. I'd like to ask you all here, what your opinions are on these. I'll list the popular points in the poll, but feel free to add your own in the comments! But do try to pick at least one of these that most fits your reasoning, if you can.

So here's the question:

"What set's this work apart from my other works?"

I appreciate the feedback!
~Ray