What's a Brush Palette for? And can you make them yourself?
I just found it on SCMDraft earlier, and I have absolutely no idea how to use it...

When you're on the brush layer you can drag-select terrain/units and use ctrl+c and ctrl+v to copy/paste brushes. You can also save them to separate files.
Hold ctrl while you drag to make a non-rectangular brush.

Oh... Okay, I get it now. So it's like a super copy/paste thing?

Well, I use it a lot while I make terrain, the latest versions of SCM Draft allow you to put multiple blocks of terrain in one file, so I just get most basic blends, like I have a brush of every single cliff face, and every single cliff face when attached to water, things like that, the ability to shift select terrain is nice, since it allows me to get oddly shaped brushes too.

Yeah, that can be pretty helpful. I'm about to start using since now I know what it's for