>>29640112>I've been considering making a hack with loads of rivalsDo not do it.
Do not do it.
Learn from the mistakes of a plethora of bad hacks. The more rivals you include in your hack, the more forgettable they become. To use Ruby Destiny as an example, as shitty as Reign of Legends is, I can actually remember the two rivals being Blitz the Edglelord and that one chick who ends up as the eighth Gym Leader, and that they were friends with each other and both wanted to protect Lugia from being corrupted by shadow energy, even though edgelord was at risk of being corrupted. They were badly written rivals in a game with a forgettable overall plot, but they were the ONLY rivals so it doesn't tax your memory while playing the game, and when they show up you know exactly who they are and understand why they're there when they do.
Meanwhile, I can't remember half of Life of Guardians rivals (there was that dude named Light who had a Zoroark, that one ranger chick whose guild you can join during that fake morality bullshit Jagold threw in halfway into the hack then almost immediately dropped and put you on the good route for the rest of the game, there was that alternate universe version of you that was the opposite gender, and there was that one guy who gets really mad at you and battles you three times in a row with the exact same team. Fuck the rest) because the author decided there needed to be more than fucking ten.
Rival spam is bad, man. I wouldn't go above three rivals, even XY had its rivals be undeveloped (even by Pokémon standards) because there were four of them.
If you want NPCs to appear regularly, try introducing a Looker/Eusine character; someone who's chasing something and progressing either with or without your help, and might battle you, but isn't a regular rival. They have their own goals unrelated to yours, and cross paths incidentally, and maybe seek you out specifically during the climax of their arc since you've proven to be helpful.