If I could suggest some flat color pickguards as an option. I think they might look pretty good. Here are black, graphite-gray, some-kind-of-blueish-gray, white and biege pickguards.
These are Jjango's renders, of course. I've added pickguards on top in MS paint, so it doesn't look that good. I like the graphite pickguard on both basses here and the penguin.. White-blueish looks kind of cheap; I just couldn't get it right, and I had hoped of it being the best combination.