Calico describes a coat, not a breed: white with patches of orange and black, or the softer cream and gray version. The pattern appears on domestic shorthairs, domestic longhairs and a number of pedigreed breeds, which is why calicos come in so many sizes and fur lengths. Most weigh somewhere between 6 and 12 pounds.
Most adoptable calicos are domestic shorthairs, so their care looks like that of any house cat: vaccines, dental care, steady weight and regular play. Coat color doesn't predict personality, so spend time with a cat and notice how she handles being held, noise and other pets. Many live 12 to 18 years indoors, which is a long commitment worth planning for.