is there any type of clay that we dont need to bake?

Answer 1

The clay here in California is already baked by the sun and makes hard, heavy blocks when cut out. A man in the Central Valley dug a home out of it in an orchard which has been featured on several TV show. It's a constant 60 degrees F and doesn't need painted.

Answer 2

The second answer is ALMOST right. At michaels you can buy clay that looks, feels and works just like regular clay but dries hard overnight. It also now comes in all colors. I have done some nice work with it and it accepts paints and markers well when done.
Secondly if you are doing someting like the impring of a babies foot and want something truly non toxic, PlayDoh will air dry nicely in just a day or two or in an oven at 100 degrees in an hour or so. It too will accept pigments. I like to spray a clear matte or glass laquer over the play doh when it's done.

Answer 3

There is only one true air drying clay. It is available in Art/Craft shops in pound packs in either white or terracotta. It dries to a hard paintable finish but is not suitable for outdoors.
There are several oven bake clays like Sculpy and Fimo which can be baked in the home oven at low temperatures,They are used for beads and miniatures.
Good luck and happy potting.