Oh wow, I vary a lot! My favourite OC is Khole, who is currently my signature. As you can see, she's white with crimson. Her design used to be slightly more subtle, with her marking being blood red, but that's changed quite a bit.
Overall, if I'm just making something off the top of my head, it usually tends to fall into the trap of monochrome, mostly being shades of gray for the pelt, lighter gray or white the undercoat, and then 10 10 10 black or darker gray for the markings. But I usually have a reference picture and GIMP open to take colour swabs of a dog or deer or whatever since GIMP uses the same type of sliders as FH, and I just use that and try to match up the markings as best I can.
I've noticed that the "white" undercoat of an animal is never white-- it's almost always cream or very light gray.
If I wanted to be a sparkle bomb, I'd set all sliders except the eye to have absolutely no blue or green, or make the blue and green even. Then for the eyes, just some random colour. My first sparkle bomb had a white pelt, a 5 5 5 black undercoat, and then hot pink tiger stripes with the same colour mane. I might remake that sparkle-bomb when I get the chance. . .