The others don't look as different, though. The Ladybug earrings are the same shape either way, just they're red with black spots when she's Ladybug—or, apparently, when Tikki picks them up to go find Marinette—and plain black, or possibly very dark red, when she's Marinette. The Black Cat ring doesn't change shape either, it just goes from black with a green pawprint to plain silver. Fox, Turtle, Bee, and Rabbit Miraculouses, same pattern. (I don't think we've gotten a good enough look at the Monkey, we haven't gotten a high-quality look at the Dragon, and we haven't seen the others up close enough.) The Butterfly only has its wings when Hawkmoth's transformed; it's a small oval otherwise.

That said, I am informed in comments to my today fic that when Marinette was wearing the ring, it was rose gold, not silver. I need to check this. The Ladybug earrings have been repeatedly shown with butterfly earnuts, which were not a thing a hundred years ago, so the Miraculouses looking different when inactive for different wielders is not implausible because clearly they change shape to blend in with current styles anyway, but I am not sure I believe rose gold. (I ain't changing my fic if I was wrong, though.)