Small building design inspiration can come from many places if you are on the look out. Below are some small buildings located at the Great Escape, a Six Flags amusement park located in Lake George, NY. The park originally opened in 1954 and was named Storytown. Many of these little buildings date from the original nursery rhyme themed park, making them officially historic (over 50 years old). While you may not want a shed shaped like a pumpkin, there are design elements that may give you some inspiration.
I didn’t get photos of all the great little structures since there were so many, but hopefully this gives you a sense of the variety of character you can have with tiny buildings and sheds if you are creative with design elements.