Liability Coverage- This is a basic component of most car insurance policies. If you have adequate liability coverage on your own vehicle (check with your insurance agent), you can skip this one.
Personal accident insurance. This will cover your medical bills in the event of a crash in the rental car. As long as you have personal injury protection or medical payments coverage on your auto policy and reliable health insurance, you may not need this coverage.
Protection you may indeed need:
Collision damage waiver (CDW)/loss damage waiver. This is not an insurance product, but rather a waiver that transfers financial responsibility from you to the rental car company in case of damage or theft, or for the time a car cannot be used because it is being repaired.
Personal effects coverage. If you have a homeowners, renters or condo policy, your personal items will generally be covered if they are stolen from a rental car. Review your policy documents to be sure you elect this coverage.