Which cartoon has 3 letters?

Answer 1

There aren't many but a quick look at the list of animated programs on Wikipedia finds ... Dot, Boj, Zou, Mad & Boo. I only went back 20 years.

Ben 10 technically only has three letters in its name along with two numbers.

There's G2G but that's of course two letters and a number. There's also BB3B which is technically three letters & one number.