Some riders can include coverage for children or grandchildren, some remove the requirement of premiums in the event of extreme illness or injury, some add cover for accidental death, and many more. (en.wikipedia.org)
Core vaccinations are designed to protect animals from extreme illness or disease and include: the rabies vaccination (in some areas), CDV (canine distemper), CAV - 2 (canine hepatitis virus or adenovirus - 2) and CPV - 2 (canine parvovirus.) (caninejournal.com)