The phrase "rare exceptions" refers to situations or cases that are unusual, uncommon and occur infrequently. It implies that these exceptions do not follow a general rule or trend, but rather they stand out as unique occurrences. The term is often used when discussing statistical data or patterns in order to acknowledge that there may be some deviations from the norm. In essence, "rare exceptions" indicate something that happens infrequently and does not represent the majority of a given situation.