Tamagotchis are known for being very brightly-colored, and I've collected the whole spectrum.
Newer Tamagotchis have been criticized for being "too pink," but it's a nice switch for me, because I acquired mostly cooler colors in the past. Now my collection is more varied and interesting!
Tamagotchi shell colors and designs tend to reflect the type of pet that resides in the device. For example, my Tamagotchi Ocean is blue and clear with wavy lines, the Tamagotchi Caveman is brown and earthy with a bone motif, and my Tamagotchi Devil is black with bat wings. Newer Tamagotchis tend to have a very cute, princess-like feel, with sparkly pink and purple shells.
Devices are not shown to scale.