Google continues to give next to no information, so I went on Tumblr to see what patterns I could find in natural kei pictures:
One thing I noticed is that, although muted colors are the most common, there are also pastels and even some bright colors (not neon or anything, just brighter colors like in the picture I posted before). Sometimes there were outfits that had bright accents, like this:

Also, there was lots of layering, and skirts tended to be about ankle-length, although there were some outfits that had skirts going as short as knee-length. Layers included shawls, skirts, vests, cardigans, aprons, lacy layers.... It's a very soft look, and I like it a lot.
I know I already mentioned the color variation, but I'm going to mention it again; this seems to be one difference between natural kei and mori. Mori tends to stay with the dusty colors and muted hues, but natural kei seems more... lively.
Examples:


See what I mean? Btw, an example of pastels in natural kei:

So, natural kei seems quite varied, and I'm doing more research through looking at various natural kei photos. I really do love this style!
Should I post more info as I come across it to this thread, or should I make a thread dedicated to learning about the fashion, or something else? (Sorry, pretty new here.)