This is great and I'm using it in my game but it's difficult to use because there is no tilesheet PNG or PSD to import into Unity. I can use the individual tiles but they are scrambled when I import them, so they don't look nice and orderly like the previews. Your paid assets include files like these, so it makes the workflow between your paid and unpaid assets different.
Edit: Actually, importing these has proven to be a huge task compared to assets that have the tile-map included. I haven't been able to get Unity to create a tile-map without errors yet and every time I try I generate 55+ assets.
Edit 2: Got my import settings correct finally.