When I downloaded a builder kit from the unity assets store it gave me a texture map with all different kinds of blocks textures in it. However I wanted to add some extras colors etc to the textures. What I’am doing right now is duplicating the texture map and opening it in photoshop for each new adjustment I want to make. This doesn’t seem like a good way of doing it. I also was wondering how I could add more textures in one texture map, do I need blender for that? And where can I learn more about coding texture maps and understanding them better? I would really appreciate any help.
The thing you are talking about is called an “atlas”. I believe Unity can create an atlas from sprites in your project and if not, there are plenty of assets that can do that for you, no need to open other programs.
As for creating one big atlas for everything that’s usually not possible. Unity has a maximum size for a texture so you would eventually run out of space. Also I’m not sure, but I think when you want to use a single sprite you have to load whole atlas, so with one giant texture you would have to constantly keep it in memory which is not ideal