so there's a blog that only reviews Horses in video games. it's literal only scale to rate games on is "how good are the horses and how much can i interact with them", you can find it here https://www.themanequest.com/

this inspired me:

if you rated games based purely on one impossibly niche element, solely ranking them on how well they do X, what would your niche be?

Example that i came up with:

how tasty looking the potions are. you go through and play every various jrpg, and you evaluate

-what potions it has
-what you use to craft them
-how people react to them
-how they look in game

and then you rank them from 1-10 on how tasty you think they'd be.