Pottery Styles

I'm designing a country. Medieval base (reasoning that they cannot go any further than they have because this country is isolated and has no fossil fuels) with a semi-tropical climate. I reckon that they would not have done what Europeans did and invent the barrel; I think they would have stuck to what the Ancient Greeks used and proliferated lots of pottery.

Pottery is made in six places in this country; I am trying to identify the style and the type of clay used for each of them. As you can see the decoration styles are distinct. Estuary and Deltaside have the ubiquitous kaolinite; porcelain.

I cannot for the life of me remember where I found the outline of the round pot. It isn't mine - I didn't draw it, I just edited on the pattern and the colouring. If it's yours drop me a line, please.