I'm going to start this year with one of my favorite mediums: pastels. I've posted a couple pastels styles before (here and here), but this one is different because it doesn't favor black backgrounds. It's much more flexible with the color palette overall.
It has a highly stylized illustration style reminiscent of Disney (though it was not trained on Disney images). It's particularly good at portraits and minimalist compositions, but it can also do full scenes if you specify that in your prompt.
I have noticed a quirk with it often making characters with closed eyes. Specifying an eye color is a good way to get opened eyes on characters with this issue. It also likes to put a character's hands in their "pockets". Prompting for them to hold something is one option to resolve this, though sometimes the hands being hidden on SDXL isn't a bad thing.