Unity Texture to Normal Map Converter
This tool will convert any texture to normal map that you can use in Unity!
Right click on the image -> Save Image as...
Further recommendations
After importing the result image in unity don't forget to change settings for the texture.
Texture Type - Normal map
Texture Shape - 2D
And don't forget to press Apply
Now your normal map is ready to use!
Gradient Maps
Industry-standard technique right in the editor!
Easily create color variants directly in the engine without additional sprites.