Are there medical conditions in which there are chills or rigor, but without fever?

Not likely. Chills and rigor are synonyms and are seen due to the release and action of cytokines and prostaglandins as part of the immune response which also increase the body's set temperature in the hypothalamus. The person then feels cold with respect to its environment and so has chills. They happen, therefore, during a high fever. Rigor mortis is a condition after death where the limbs stiffen.