One of those tools, the Reviewer Grabber, uses a piece of software that searches through the Amazon database to find active reviewers who previously reviewed similar books to yours. (build-creative-writing-ideas.com)
-- and they have over 10,000 active reviewers out of 36,500 users. (thecreativepenn.com)
Managed peer review process for academic manuscripts, which entailed contacting potential reviewers, corresponding with active reviewers to ensure deadlines were met and collecting their reports. (jobhero.com)