Katty was named after Katty Katswell, Kitty's evil twin sister from T.U.F.F. Puppy, another show created by Butch Hartman. All three characters are cats and are voiced by Grey Griffin.
Katty has some similarities to Gary from SpongeBob SquarePants. Both are pet cats (or, in Gary's case, a pet snail who acts like a cat) voiced by the same voice actors as their owners (Katty is voiced by Grey Griffin, the voice of Veronica, while Gary is voiced by Tom Kenny, the voice of SpongeBob, respectively), and both have great intelligence.
Originally, Katty would've been voiced by Dee Bradley Baker, before WikiaIvan1997 decided it would be cuter to have Grey Griffin as the voice of Katty.
Katty really likes Timmy, and is prone to purring when she's near him.