Here are a few .PRO domains that I found available. They are typically $99 per year, and can only be registered at a few registrars such as http://www.encirca.com/
Gasoline
Inventory
Drive
Driving
AskA
Drain
Workout
Interest
Birth
Claim
Audit
Auditor
Baker
Bakery
TaxLaw
Scout
Biology
Flying
Reading
Russian
Safari
Selling
Geology
Fencing
Barber
Label
Drum
