Neither is correct as written. It should be "There are hundreds of toys in his collection."

There are a hundred of toys in his collection. (If you know that he has exactly 100 toys). If you don't know the exact number, but you want to say that he has lots of toys, more than 100, you can give an approximate quantity. There are hundreds of toys in his collection. (He may have 200,300..... and so on toys.)