I’ve used mostly Cone 6 clays from Pottery Supply House:
The ones I’ve used the most are:
CONE 06 WHITE GROGGED CLAY: The Review: The grog allows you to work soft or rigid with ease. This is a beginners dream clay to use.
CONE 06 RED GROGGED CLAY: The Review: This is the least favorite to use. It fires off the red and needs specialized glazes.
WHITE GROGGED STONEWARE:The Review: Excellent clay for larger structural pieces. It can dry to leather hard slowly enough to work over a few days and is rigid enough for the most architectural structure.
SHEBA RAKU CLAY: The Review: In its raw state, it is an ugly finish. It changes the chemical reaction and thus the colors of the glazes used on it. It has a finer grog in it and is a great clay for beginner hand-builders. Oddly, it loves Pete Pinel’s green glaze. Also works beautifully with matte glazes.
CONE 6 PORCELAIN: The Review: This was a challenge to use. One needed to work it faster because if it dried too fast, it would crack. It’s elasticity while in the wet-leather hard stage was fun to play with and allowed to melting appearances. It took stains very well and loved my pure pigment glazes.
BLACK CONE 6 CLAY: The Review: This worked like a tinted porcelain. It didn’t hold glazes or stains in the way I expected and seemed to give the best results when left un-modified by glaze or stain. It held up well to being mixed with gorged clays. The shrinkage was minimal, compared to white porcelain.