http://www.amazon.com
Amazon.com offers book reviews of many of the book titles it sells. Some reviews are by professionals; many are by readers. Find a book and scroll down its entry to read the reviews, where present.
https://complete-review.com/
Contains a selected listing of old and new book titles with reviews and links to more reviews.
https://www.goodreads.com/search?
Offers millions of book reviews contributed by its community members which include librarians, journalists, and many other readers.
https://www.slj.com/section/reviews
Features reviews from School Library Journal from the most recent twenty-four months. Browse by genre, grade level, award winners and other criteria.