My favorite Spoonflower fabrics for sewing doll clothes are the Cotton poplin (pair with the Organic Cotton Knit for stretchy items) and the Organic Cotton Sateen (pair with the Cotton Spandex Jersey for stretchy items). More in detail about these fabrics below.
For my Cut & Sew dress prints, I recommend the Cotton Poplin fabric from Spoonflower. It is thin and easy to sew and has the added advantage being a choice for Fill-a-Yard purchases. Another good option, in my opinion is the Organic Cotton Sateen. Here is a comparison of these two fabric choices.
Cotton Poplin (left) vs. Organic Cotton Sateen (right)
FABRIC COLOR: The base fabric of the cotton poplin is what I would call a "natural" white, vs. the brighter white of the organic cotton sateen. As a result, the color of the print on the fabric will look a bit different on each. It appears that the print is more defined on the poplin than the sateen, but I think that might be due to the naturally darker fabric base.
FABRIC TEXTURE: It's not easy to tell from this photo, but the sateen (right) is smoother with a slight sheen, while the poplin (left) is flat. This might make the sateen a better choice if you want a somewhat fancier look, although it is not too shiny by any means.
FABRIC THICKNESS: The poplin (left) is thinner than the sateen (right) which makes it a bit easier to turn out the shoulder seams. On the other hand, thickness of the sateen feels a little more expensive (which is it, by a few dollars).
FABRIC DRAPE: Both the poplin (left) and the sateen (right) have about the same stiffness as an average quilting cotton. I don't find it necessary or helpful to wash them prior to sewing as that can introduce pesky wrinkles (and the fabric may shrink). If you do wish to wet the garment after sewing, I suggest letting it drip dry without squeezing to minimize wrinkles.
I will probably choose the cotton poplin in most cases, but it is ultimately a matter of taste. I think the natural color of the poplin is more in line with the vintage aesthetic of my dolls. The sateen is good for a party dress. While I tested other fabric choices, these two were my favorites from Spoonflower's woven fabrics at the time of this writing.
FOR KNITS... I recommend Organic Cotton Knit to go with the poplin as it has a creamy base color and the Cotton Spandex Jersey to go with the sateen as it is a brighter white base.
You can purchase all of my fabric in my Spoonflower shop here: