That depends on the kind of business you engage in. All business need basic liability to protect them against acts of owners or employees for which the business might be considered legally liable. Professional service providers soften need special liability protection. Examples might be professional liability protection for lawyers, doctors, architects or software designers. Another example are businesses that manufacture or distribute a product; they typically need product liability protection. It's always a good idea to review the kinds of liability exposures your business might have when updating or initiating an insurance program.
Businesses that own autos or use non-owned autos in the conduct of their business will probably need a business auto policy.
All businesses have property which can be divided up into several categories: office or other equipment, inventory, real property, etc. and it is a good idea to think about your ability to replace any damaged or lost property in these categories. If the possible amount of loss exceeds your comfort level then insurance might be a good altenative.
You need to think about how long you could afford to be out of business. Insurance, known as business interruption insurance, can pay suppliers, salaries and other costs you might incur even if your business income were to be interrupted by a covered cause of loss.