Rear ends, I have noticed Red Bull & Toro Rosso are virtually identical even though Toro Rosso is meant to be on its own.... I think they're lying.. but heres some pictures of different ways the teams have gone about designing their rear ends:

Red Bull

Ferrari

McLaren

Mercedes

Sauber

Force India

Renault

Williams
Sorry it was so long.. but its clear all teams have very unique designs.
Rear wing design is surprisingly unique too. The most notable are Renault, Williams & Sauber.
Also the position of exhausts are unique alone with any cooling ducts. I think Toro Rosso & Red Bull's holes in the middle are to cool the engine, letting air escape. McLaren have a slit in their fin which was previously overlooked too.