In a lot of places the entire county is a school district, so there are a lot of schools, so they have more mascots. In my county there are 18 school districts. Each with varying numbers of schools. They vary extremely geographically as well. Some are like a square mile others are over 150 square miles.
Some districts have only 1 elementary, 1 Middle, and 1 High School. Others have 14 elementary, 4 middle, 1 High, plus 3 themed gateway schools.
For the most part each of these districts have one mascot. Trojans, Bulldogs, Spartans, Scouts, Red Knights, etc So Reading Red Knights, Wilson Bull Dogs, etc. The elementary, Middle/Jr High, High, etc all refer to themselves as the district mascot even though you might have lots of different school names. So Conrad Weiser East Scouts. Conrad Weiser High Scouts, etc.
Some of the schools I have worked with have quite interesting mascots; Slaters, Koncrete Kids, Bullets
It is one thing I have found that definitely varies from place to place.