PokemonGameEditor VS universal-pokemon-randomizer-zx

this would be super easy to do, even if you don't want to get into the newer more complicated stuff like decomp, there are plenty of older tools out there like Pokémon Game Editor and Gen III Rom Hacking Suite that would work just fine if all you're doing is changing names of Pokémon, moves, items, trainers, etc.

Download Page Link: https://github.com/Gamer2020/PokemonGameEditor/releases

editing pokemon data should also be fairly simple depending on what you want to do. for this i recommend pokemon game editor. it has a variety of functions, but you can load your rom and pick the pokemon editor. pick the species you want to edit in the top-left. the species' catch rate is in the base stats tab, next to its other stats like HP and attack and so on. you didn't mention wanting to change evolutions, but that should also be really easy, and it's a popular edit in case you want to get ride of trade evolutions. just go to the evolution data tab and change "condition" from "trade" to something else like "level".

Ideally this feature gets merged into the actual project over here, but I was too excited to wait for that to happen. But please understand this is an extension of an already fantastic tool called the Universal Pokemon Randomizer ZX.

Want to run my seed? here it is (mirror), this file is to be used with Universal Pokemon Randomizer zx.

Another tool you could use to get a Yanmega as a starter is Universal Pokemon Randomizer ZX. Even though its main purpose is to randomize roms, you can also use it to just change the starter selection.

That guide is outdated. Nowadays, you can open a regular 3ds rom in Universal Pokemon Randomizer ZX, and output either a LayeredFS patch for a real 3ds, or a cxi file for Citra.

This randomizer supports gen 6 and 7 too I believe

Here is a link for the Randomizer on GitHub.

https://github.com/Ajarmar/universal-pokemon-randomizer-zx/releases Universal Pokemon Randomizer

Pokemon Randomizer ZX is a Java app that can randomize anything from Game Boy to 3DS. If you are not able to run Randomizer ZX, you can use this web version which can randomize anything from Game Boy to DS.