Hi! Love these assets dearly. But when I first downloaded them to play with in Godot, I noticed that after import their materials and textures were showing up blank. So I opened the blend files in blender to investigate what the matter could be, and noticed that for each asset which this was happening to the material output was not connected to the image texture in the Shader Editor. Apologies if that doesn't make exact sense, I am completely unfamiliar with Blender.
But after going through the asset library and connecting these two nodes in the Shader Editor, I now have all the assets working as expected after import in Godot. Unless there is a reason these were disconnected originally (not all assets were, but a large large portion are) then maybe you could make this change for the next release? Alternatively, I have done the work myself, and would be happy to share them with you craigsnedeker.