Sanrio is a Japanese company that specializes in designing and producing cute and colorful characters. Some of the most popular Sanrio characters include:

1. Hello Kitty - perhaps the most famous Sanrio character, Hello Kitty is a white anthropomorphic cat with a red bow and no mouth.

2. My Melody - a pink anthropomorphic rabbit with a red hood who loves to bake cakes and other sweet treats.

3. Keroppi - a cartoon frog with large eyes and a big smile who wears a green shirt and likes to play and swim.

4. Little Twin Stars - two cherubic twins named Kiki and Lala, who have matching angel wings and live on a fluffy cloud.

5. Cinnamoroll - a white puppy with long ears that curl up at the end, and a tail that looks like a cinnamon roll.

6. Pompompurin - a golden retriever dog that wears a brown beret and enjoys eating pudding.

7. Gudetama - a lazy yolk with a "meh" attitude who likes to lay around and sleep.

8. Badtz-Maru - a black and white penguin with an attitude who likes to play pranks and skateboard.

In addition to these popular characters, Sanrio has created many other cute and colorful characters over the years, such as Tuxedo Sam, Pekkle, and Kuromi, among others.