Art Replacement
An Art Replacement mod is a quick way to mass-replace the art of the existing symbols and items without having to create a new script file for every symbol/item we want to modify.
In order to create an Art Replacement mod, we simply need a file named art_replacement.gd in our mod's scripts folder. The content of the file must be as follows:
extends "res://Mod Data.gd"
func _init():
mod_type = "art_replacement"
After creating our art_replacement.gd file, we can create new PNGs with art of the symbols and items we wish to modify. However, we do need to name each file exactly the same as the symbol's or item's type. For example, our art folder would have these files in it if we wanted to change the art for Gambler, Thief, and Eldritch Creature:
gambler.png
thief.png
eldritch_beast.png
Note that Eldritch Creature needs to be named eldritch_beast.png as it -- and some other symbols/items -- have slight caveats to the naming of their type variables.
And just like that, whatever great art we've created in the PNGs will replace the art for Gambler, Thief, and Eldritch Creature respectively!
(The above art is from Shadowed Texture Pack by Anubscorpiak)