Improvements
Since the shovel was invented it has taken on many forms. Almost every single form was made for a specific purpose but some of the variations are more versatile then others. Some shovels are made for a specific job while others are made to be better at it's job than it's predecessor. Shovels that are made for a specific job usually have a physical feature that helps them do their job better than a normal shovel.
Many times a variation isn't made for a specific purpose it is just trying to make a tool better at it's purpose. Unfortunately most variation barely change the actual shovel but just add gimmicky features.
Improvements
Many variations are very helpful like the Sack master, which was featured on the TV show American Inventor.
The Wovel is also an invention that seems gimmicky at first but is an amazing time and effort saver with it's ingenious design.