I like the idea of flash non-fiction, but I never seem able to find much about it. Not one-liners, rather in the 3-5 paragraph range, which might be understood as being an article (ex. newspaper/magazine), only articles are usually longer.

I'd love to find an example of a media outlet that does such a thing, albeit with mid/high-brow content.

365 tomorrows might be the right length for you: https://365tomorrows.com/ (only science fiction)

http://sixsentences.blogspot.ch/ is pretty good sometimes.

I once had a directory with huge number of fiction books, and I've sorted it by size asc. Most of the first few dozens of entries were amusing.

Which in turn reminds me of Hemingway's shortest short story:

'For sale: baby shoes, never worn.'

There's no evidence that it was Hemingway who wrote it.

https://en.wikipedia.org/wiki/For_sale:_baby_shoes,_never_wo...