I'd like more in the world building department. Maybe a history book or NPCs who tell us the story of the first Pokemon Battle. I'd imagine it would be like this, "Long ago there was a massive war, all regions fought each other in this war. During the final battle a trainer from each region came forth with three Pokemon, each a water, grass, and fire type. Yes they are the starters of each region. No one knows who won, no one cared, what mattered was that they all came to an understanding through this battle. And this is why we use the three starters to this day."
Also maybe a little reference to maybe why HMs aren't a thing anymore? Nothing major, it doesn't have to be dark or anything like that, maybe something like, "After the Team Plasma incidents people started to protest the use of HMs because it encouraged people to force young Pokemon to learn weak moves to move between towns. Ride Pokemon/(other substitute) was found to be better because they could be called on at any time and the Pokemon doesn't have to battle/will likely be strong enough to protect itself."