What seems like ages ago I wrote a simple python script that randomly spit out content rating, category, and main characters for use in an MLP fanfiction. It’s not up to date, missing some characters, but you can try it here: https://repl.it/Idfc/0 (just click run.)
an example of what it outputs:
['Alternate Universe', 'Horror', 'Thriller']
['Everyone']
['Aria Blaze', 'Prince Blueblood', 'Spa Ponies']
A horror thriller for the whole family would be an interesting feet, perhaps not possible, but still an interesting challenge nonetheless. Changing the numbers on the last three print lines change the number of main characters and such. This helped me through a bit of writers block once and I’m certain it could for others.