The Asset Builder is a tool for choosing, recolorizing, and stacking images together of the same type.
Right now, only one asset pack is provided with the tool and it uses the assets provided by the Intersect MMO Engine. You can find the assets here.
Head over to the releases page to get the program for yourself, or launch the script with poe run (poethepoet) after installing the dependencies.
When saving, all options are stored into the png file output in a text block. To get an image without this data, Export instead.
If you want to build an executable for yourself based on the python script, use poe compile (poethepoet)
Note that after building, the "i" folder and the "packs" folder should be included next to the executable to properly use the tool.