Several companies manufacture polymer clay. The brands differ in plasticity, strength, translucence, curing temperature, and flexibility after baking, and each company has its own selection of colors. The clays described here, in no particular order, are the ones I am personally familiar with.
ProSculpt requires very little kneading and blends without showing seams. When cured, it becomes extremely hard and durable, with a translucent, fleshlike color.
Super Sculpey is available in a semi-opaque beige that is easy to condition right out of the package and holds detail extremely well. It is shatter- and chip-resistant after curing. Super Sculpey is also available in a firm gray color used in the movie industry.
Super Sculpey Living Doll is specifically formulated for dollmaking. It blends easily and is strong and durable after baking with a slightly matte, fleshlike color.
Premo! Sculpey is soft enough to blend easily but firm enough to hold fine detail. Premo! retains flexibility after curing and is very strong.
Kato Polyclay conditions easily and is flexible and durable after baking. The flesh color cures to a translucent finish.
Cernit is a soft clay with a porcelain-like finish when cured. Strong and sturdy, it is available in several excellent flesh tones.
Staedler FIMO Puppen (German for doll) or PuppenFIMO is especially suitable for dollmaking. It holds detail well and is pliable after baking. It is available in several flesh tones with semimatte porcelain finish.
Staedler also offers several different formulas of clay besides Puppen−FIMO that can be used for sculpting but are more often used for other applications.
Polymer clay is available in many brands and colors, in individual packages, multipacks and sampler sets.
Which clay is the best? Whichever one works for you. Each clay moves differently and has a different feel; some you’ll love and some you won’t. I recommend getting a small quantity of each and experimenting until you find your fave before you invest a lot of cash.