I've now started doing some basic art design. This has forced me to do something I never, in the course of my entire existence, thought I'd be voluntarily doing: art history research.
I can't recommend this article enough. In it, the author analyzes the art styles of the two main factions in Arcane - the orderly, wealthy Piltover, and chaotic, destitute Zaun.
Piltover uses primarily artistic cues taken from the phase of art called "Art Deco", characterized by geometric shapes and patterns. On the other hand, the underworld of Zaun is stylistically inspired by "Art Nouveau".
The Art Deco style, aka, Piltover, is more appealing to me, and also much more practical for 3D printing and my extremely limited art skills, so I'll be moving to design based on that.
Here are some screencaps from the show I've been using for inspiration. Note the geometric shapes and clean lines.
I've decided to theme this cat feeder with hexagons, because they're a very fun mathematical shape, are very versatile, and have lots of fun opportunities.
Here's what I have as a starting point. The copper color are inset pieces that I'll print separately and spray paint copper-colored (color subject to change).
Finally, it has occurred to me that Arcane is not exactly steampunk, due to the presence of magic. After some research, I've seen a few folks recommend calling this magepunk. There's also a subreddit dedicated to something called Aetherpunk, which I think is pretty similar to what I'm looking for.