Professional liability insurance and public liability insurance may also be required depending on what type of business you run. Some businesses are required to have one or the other due to their profession e.g. lawyers are required to have professional liability insurance.
Failing to obtain the right insurance for your business can lead to fines from government authorities or, worse, a compensation claim that your business is unable to handle. Be sure to research all the options and take any advice needed before making a decision in this area.