Change Pokemon Menu Sprite

[JustIChristopher]

So I changed the colour of Rattata to make it black using G3HS, which worked out fine.

When I change the menu icon for Rattata, however, others who use those colours are also changed (such as NidoranM).

Is there a way to change just one?

Cheers.

 

[DrFuji]

All Pokemon icons use one of three palettes that are loaded when the party screen/ PC is accessed. These three palettes are shared by all 386 Pokemon so (as you've seen) a single change will affect any other Pokemon that uses the colours in that palette. These three palettes are used due to restrictions in the number of sprite palettes available on screen, maxing out at sixteen. If you were somehow able to give every Pokemon icon a unique palette the game wouldn't like it if you opened up a PC box of thirty different Pokemon. At best it would start overwriting, at worst it would crash, regardless, it is impossible for the game to give a unique palette to every single Pokemon without overhauling other core mechanics of the game.

A case could be made for possibly adding up to five more available custom palettes by utilizing the Dynamic OW system and using the unused palette slots when accessing the party/ PC screen. This is just a theory and I have no idea how to implement it/ don't know if it will break anything else.

I'd highly suggest keeping to the standard palettes and just working with what they give you. From the looks of it you can emulate Alolan Rattata's colours pretty well with the first icon palette.