Tabby Cat is a fun Chrome extension which generates and displays a new feline friend for every new tab page.
The graphics are basic - outline, eyes, nose, shadow - and they don't change much, but there's scope for a little variation here. Different colours, tiny companion kittens, toys like balls of wool, odd quirky images (there's a flying kitten with a wand and a cat with a unicorn-like horn), and every cat has its own randomly generated name: "Vanilla Sneaker", "Snuggly Marshmallow", "Leaping Princess", "Wise Meow" and more.
A few of the images have a little scope for interactivity. Move the mouse cursor to the cat's head and it sometimes reacts.
If you do find a cat or scene you like, clicking a Camera icon top right saves it online and gives you a short URL like http://tabbycats.club/8ihx1a to share with others. There's no cost, no registration, it just works right away.
There's not much variation in the auto-cats, and you can't do a lot with them, either, but it could be fun for kids or feline fanatics in general, and the snapshot sharing is a nice touch.