There are quite a few famous Instagram cats, but one of the most well-known is undoubtedly Grumpy Cat. With over 2.4 million followers, Grumpy Cat (real name Tardar Sauce) is a superstar in the online world, and has even been featured on TV shows and in advertising campaigns. Other popular cats on Instagram include Nala Cat (1.6 million followers), Maru (1.2 million followers), and Oskar the Blind Cat (960,000 followers). These furry celebrities have won the hearts of millions of people around the globe, and show no signs of slowing down any time soon!