As inferred by their name, besides Chip, Mrs. Potts had at least six other children (according to Marvel Comics, including Chip, she had 12 children overall). Like their brother, the children were transformed into a teacup set.
Beauty and the Beast
They were first alluded to when Mrs. Potts was putting her son, Chip, into the cupboard for the night, despite the latter's protests, shortly before Belle entered the kitchen after leaving her room during the first night at the castle. Despite this, however, they were later awake and helping prepare Belle's meal (Be Our Guest). They aren't seen until the climax of the film, where they aided their mother in driving out the invading villagers, more specifically pouring hot tea onto a bald, mustachioed baker. They aren't seen in the film after this, although they are implied to have regained their human form.