The category I started prepping for last year before I got too busy was the Light of Hope Ending, which is a nice showcase of each faction, plus is sort of the 'true' ending anyway, and (based on my early routing) can be done in less than an hour.

I think a category for each faction individually is also a no-brainer.

Hoping to pick this up again in a month or two after real life gets out of the way...