Frost cloth is a great option to save your plants from severe temperatures. Frost cloths tend to store the heat beneath the covers and help plants grow despite temperatures that are lower than ideal for them.
Row cover is also known as a floating cover, which is used to protect plants planted in rows or close together, from the cold weather. It usually comes in quite big pieces, which you could cut with sharp scissors to cover a smaller piece of garden.
Drop cloth, for instance, is also a good option if you do not have a frost cloth to save your plants from a sudden late frost. If you must use a drop cloth, make sure to remove it in the daytime if the temperature rises a bit.