Well, let's see here, we have the Bouillon Soup, the Round Bowl Cream Soup, the Gumbo Soup, the Place Oval Soup, and the Desert Oval Soup. If there are more, spare me. The Bouillon spoon is smaller to fit the thinner broth. Cream soup spoons are larger than bouillon but smaller than gumbo and have round shallow bowls. These spoons are all round while the other two are oval in shape.
(Boullion Soup spoon shown in Buttercup by Gorham)
(The Gumbo Soup spoon shown in Louis XV by Whiting)
(Cream Soup spoon shown in Sir Christopher by Wallace)
(Oval Soup spoon shown in Pompadour by Whiting)