There are many uses for Baby blankets besides it's main purpose of keeping the baby warm. These blankets also come in handy as a receiving blanket when changing a baby in the bathroom changing stations. Also, it can be used as a transportation vehicle to carry your baby from place to place.
Babies who less than a year old are the ones that we most need to carry receiving blankets for. Since you have to carry these around, the main features of these types of blankets is that they be lightweight. The second necessity is that they be breathable. The best materials that meet both these criteria is cotton, a natural material. These blankets will usually need to be washed a lot also, so make sure that the one you get is machine washable.