Perhaps you're thinking of:
* The Maine Coon: Known for their large size, they can reach up to 25 pounds and are considered one of the largest domestic cat breeds.
* The Ragdoll: While not as large as Maine Coons, Ragdolls are also known for their size and can weigh 15-20 pounds.
If you have more information about the cat you're interested in, like its appearance or any other characteristics, I might be able to help you identify it.