Cumulative data type
An interesting data type would be a cumulative one. Basically, it would be a number that can increment or decrement each day, starting from the value of the previous day.
Technically this could be achieved with the numeric type, but lets say you wanted to track the number of books in your library, or the number of plants you have that are currently alive, or your salary, or any number that might not change often, you’d have to manually enter the value each day. A new data type would cut down the manual aspect and make certain types of tracking more feasible.