Classical:Grammar Stage Science Book List(grades 1-6) Compiled by Carol Richey This is a good starter list which I've used for library book searches. It's also good to use as a spine for finding similar books under topic areas using key words.
Charlotte Mason Living Books Curriculum(grades 1-8), good for reference.
From Donna Young - "A basic a skeleton outline of science topics. Use this as a study guide to look up resources in an encyclopedia or other reference books": See here, and here for a living science book list shared on a Donna Young forum.
Public domain science books shared by An Old Fashioned Education. Some texts are included; however, many are living books. See books broken down by grade level here.