Multiple Apple Developer Accounts
Business Entities and Individuals

If you operate a legally recognised business entity, the business can have an account and you can have a personal account. You will need to associate each account with a separate e-mail address.

Consultants and Clients

If you are a consultant, you should consider one account for yourself and one each for your clients.

Personal Experience

I use multiple Apple Developer Accounts. They are associated either with business entities I am associated with, or are personal developer accounts.

As you mention, each account needs to pay the annual fee.