Ask HN: As freelancers/consultants, what tools do you use to run your business?

Hey HN, I'm a product/marketing consultant, working with several companies at a time. I'm having a hard time keeping track of tasks, billable hours, invoices and the like. Project management tools are often geared at teams trying to work together, and so have bloat I don't need (stuff like chat and forums) and don't have some things that I do (invoices, time tracking). I'm sure people have built tools to make running business like mine easier - do you know of any? Thank you!