Rare PETS are those whose Body Parts belong to the RARE tier.
When Breeding is implemented, Rare PETS will eventually become the most abundant PET type in the Rareverse because every newborn PET will belong to this tier.
None of the OG PETS will be in this category since they are assured of having at least one Ultra-Rare Body Bart.
Rare PETS can be Full-Set or Shuffle-Set, depending on their combination of Body Parts.