Most business insurance is optional. The one that isn't has handcuffs attached.
Start here, because everything else is a distant second. ARS 23-961 requires every Arizona employer to secure workers' compensation from the first employee. Part-time counts. Temporary counts. Your brother-in-law counts. There is no threshold you slip under, and it is the one insurance requirement in this state with actual criminal exposure behind it: failing to secure it is a class 6 felony under ARS 23-932.
The consequences are not a slap. Going without is a misdemeanor, with a fine of not less than $10,000 or up to a year in county jail. The state can assess up to $100,000 against an illegally uninsured employer. It can issue a stop order that shuts down your use of employee labor on the spot. And the part that ends businesses: if you are uninsured when someone gets hurt, you lose the protection workers' comp normally gives you, so you pay every bill and the employee can sue you in civil court besides.
Everything after that is judgment, and judgment is what you are actually hiring us for. Most small Arizona businesses run on a Business Owners Policy, which packages general liability, property, and business income together, plus workers' comp alongside it. Then it depends on what you actually do. Give advice for money and you need professional liability. Drive for work and you need commercial auto, because your personal policy excludes business use. Hold customer data and cyber stops being a luxury. Have employees at all and EPLI belongs on the table, because Arizona is not a forgiving place to be an employer.
What we will not do is sell you the whole catalog. Tell us what your business actually does, and we will tell you what it actually needs, which is usually less than a website like this could talk you into. Nothing on this page is legal advice, and for the employment-law side of things, get an employment attorney. We handle the insurance.