I'm familiar with all the stuff you listed, and it really just sounds like you should keep watching Magical Girl stuff to expand out the sample to see what triggers it. Try Precure, try Cardcaptor, try Utena, try Princess Tutu, try Mai Hime, try Ojamajo. 

If you think you can fairly quickly tell if something triggers it, maybe just watch the first few episodes of every precure season, since those have a lot of similarities and variables held constant between each season, so if some trigger the feeling and others don't, I think we would be able to rule out lots of different factors. 

 Interesting. I'm not sure how far removed from a magical girl context you could go and still evoke the feeling, but the first 9 eps of Hibike and the first two cours of Saki might be worth trying at some point. 

 I've watched through the entirety of Flip Flappers and Haibane Renmei, from among those seven; neither particularly had the thing I'm looking for here, as far as I'm currently managing to recall.

I'm glad something landed, if only a little bit. 

Have you tried any of these before? These aren't recs, I'm just wondering whether I can rule them out.

 I gave the manga a read this afternoon. It contained 

 of the thing than any of the examples on my noncentral-examples list, but still 

 of the thing! So that definitely seems like a meaningful data-point of some sort.

...and I think you're right that the visual component is plausibly relevant. I don't think it's a 

, per se—my first read of Of The Stars came before I'd actually consumed any of the Sailor Moon canon, so I didn't have much visual background in the series at the time, and I'm pretty sure I still perceived the thing there on that readthrough—but it seems very plausible that it's an 

, because a lot of the images-to-which-my-mind-intuitively-turns when considering Qualia the Purple's thing-having-ness are specifically visual memories of various bits from it. The two-page spread just before the end of chapter 5, the last page of chapter 6, and various of the abstract visualizations-of-Gaku-talking-to-herself-with-a-starry-backdrop scenes from throughout the second arc.

(And, when I look at my memories of Nanoha, it's easy to dig up scenes from there which feel of-an-aesthetic-category with those manga-pages, including off the top of my head the big city fight scene in Season 1 Episodes 6-7 and the city fight scenes in Season 2 Episodes 1-2 and 5. Although I have no similarly-well-defined such memories from the first two Fate/kaleid liner Prisma Illya seasons, and closer-to-as-many-as-in-Nanoha from Madoka Magica (particularly the various city shots in Episode 8), thus continuing to reinforce the "whatever visual-design-ish thing these scenes have in common, even if it might be a 

 in the mood I'm looking for, isn't the whole thing" hypothesis.)

Inconveniently, however, the thing's presence overall wasn't hugely immediately apparent as I read; it was more a product of my model-of-the-story coming together over time, including while processing it after finishing my readthrough, than it was an immediately-perceptible thing in any particular scene as I went through it; 

 I'm intuitively inclined to attribute it most strongly to the last ~third of the first arc, followed by a more diffuse spread through the second arc, but this wasn't really a thing that struck me 

 so much—its first-arc presence mostly became visible to me while I was reading the second, and its second-arc presence mostly became visible to me while I was thinking about the story while taking a walk afterwards—and this seems like it might make it hard to do the "quick scan of a few episodes per Precure" maneuver.

 Either could work, but I suspect the visual dimension of the manga might help since the stuff you listed that had the thing consisted either of works with a visual component or fanfiction of stuff with a visual component

 I read a fan-translation of the light novel ~seven years ago, but don't remember it at all clearly at this point, and haven't read the manga. I'll give it a shot!

Also apparently there's now an official translation of the light novel, for good measure, which I hadn't known about until just now. Do you have opinions on the relative merits of that versus the manga?

 Have you tried the Qualia the Purple manga?

 Symphogear sounds like a strong contender, yeah

 Among those of your recommendations I've seen so far:

I haven't yet watched Mai-Hime or Ojamojo, or other Precure series; I should probably try those each out at some point in the not-too-distant future. (Also relatively high up my current to-watch agenda is Symphogear, which I imagine will also be a relevant data-point.)

As for how quickly the thing shows itself... hmm. That's a good question, and I don't have a solid answer pre-figured-out. Next time I notice the thing in a new work, I'll try to pay more attention to the precise timing of its becoming-perceptible-to-me and report back.

Maybe like RWBY, Kiki's Delivery Service, Spirited Away, or Spy x Family could have something you like?

 I gave Kiki's Delivery Service a watch. Of these examples, it seemed most similar to Spirited Away, which I suppose makes sense given being from the same studio; I didn't find it to be perceptibly the-thing-I'm-after-here, any more than Spirited Away was.

 Neither RWBY nor Spirited Away particularly has the mood I'm looking for here based on my memories of having watched them, unfortunately, nor does at least the subset of Spy x Family that I've seen thus far. (Of those three, RWBY comes 

.) I haven't yet seen Kiki's Delivery Service, though; I'll get back to you on that one, whenever I get around to watching it.

I confess that I don't recognise any of your examples, but this is the only story I've read that comes to mind when you say 'magical girl mood':

https://forum.effectivealtruism.org/posts/mCtZF5tbCYW2pRjhi/the-unweaving-of-a-beautiful-thing

 I gave it a read; it was interesting, but not particularly in the genre-space I'm looking for here, unfortunately.

There's a certain sort of mood evoked by certain works of fiction, particularly magical-girl stories, which I enjoy a lot but which I lack any precise description or understanding of beyond an empirically-collected list of stories which evoke it. I'd like to find more such stories, and ideally a better model of what the mood is and/or what the core story-characteristics are which produce it!

Relatively-central examples of stories which evoke the relevant mood:

Less-central examples, which still have the mood to a nonnegligible extent, but more intermittently and/or mildly:

Stories which may or may not have the mood, it's kind of ambiguous and/or fuzzy in my memories:

Stories in which I haven't noticed the mood hugely much, even though one might have expected me to based on certain extrapolations from the prior examples:

Plausibly further examples exist; if I think of more later on, I'll edit them into this list.

I intend to give out 50 mana per recommended story whose conveyance-of-the-desired-mood-to-me ends up being comparable to that of the stories on the relatively-central-examples pile, 25 per recommended story which lands around the level of the less-central-examples pile, and 100 for a plausible-sounding concrete explanation of what the relevant story-characteristics are which evoke the mood and/or of what the mood itself is. (Plausibility assessed partly on the basis of whether-it-produces-successful-recommendations.)

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