Indies Today has this list of Indie Book Reviewers, dated February 2022. The 300+ reviewers are listed alphabetically, after a few promoted sites, so you will have to manually curate for your genre(s) and budget, and then approach individually. The site also includes information on best practices for how to request a review. Traditional review stalwarts Kirkus and Publisher’s Weekly also have paid reviews available for indies: Kirkus Indie Reviews and BookLife. This 2017 piece from Publisher’s Weekly lists potential places for free reviews that are open to indie authors. Given its posting date, some information in the piece may no longer be actionable. (The WGA provides links as general resources and does not endorse any third-party services or websites.)