Progressive, NationWide and Geico insurance all offer Pet Insurance and I'm sure many other insurance companies offer and sell pet health insurance.
Your own Insurance company may also offer pet insurance and all you'd have to do is ask them to be sure.
Some insurance companies only deal in pet insurance as well so you may look online for a pet insurance company to get direct pet insurance for your pet.
Trupanion is one pet health insurance company that provides both cat and dog insurance with unlimited payouts with no caps on coverage.
And I'm sure there's many other Pet Insurance companies out there.
Pet Insurance costs around $10.00 to $50.00 per month depending on the coverage you get and who you have the pet insurance with.