Propably working codes. Things like codebreakers, action replays and gamesharks. I'm using "cheats" to bypass designed limitations.
For instance:
- Wild modifiers. Don't want to play around with starters that are (once again) forced on me. I would rather gather a small team on my own. Don't need help. Advanced Starter won't change scenario in my case.
- Don't want to "catch'em all". And especially legendary ones for that is simply dumb. I remember playing Gold remake not to long ago. Developers there were pretty much forcing pokemons on the player - even legendaries. For what reason? If you remove a core of a legend from a legend, then you're also making this pokemon world soulless. Legends should be -by my own standards- unobtainable. Out there for imagination only - and also to keep things in perspective. But never reduced to a battle item or record in a pokedex.
- Walk through walls/No dark-like effect. Don't want to use stupid HMs like "flash", "rock smash" or "cut". These are a waste of space! And why even Pokemon are doing everything? This stupid trainer is just using them left and right becase His Path Must be Unobstructed? I believe that this trainer of ours should do something more than just use others. If you can't progress on you own then what type of a champion are you? Paper-made tiger? Hence i usually gather HMs and then use walk-through walls on rocks, bushes and water. I have the designed option unlocked, but won't touch it. My dude can bypass silly obstacles and swim. He can't fly; he ain't from Baam so no wings on him. Flash doesn't make any sense to me and never did. Every damn phone in our world has this basic feature called "flashlight". Don't tell me that this hyper-advanced pokedex can't even do that...
- Nature/EV/IV settings. I can save an abstract amounts of time during ev/iv training with codes. This is not for competitive purposes outside the game; just for my pure entertainment. It's not a very important thing but a feature. A small thing to do really, so why wasting hours after hours?
- Teaching techniques that are by default unlearnable to a certain Pokemon. I like "Bullet Punch". I would like if Aggron could use that. He can't. Unless i use codes. I mean, the move makes sense so why not?
Those are all just a small details but for me those are opening many doors.