How about Matchlock Gun, Christian Liberty Nature Readers, A Weed is a Flower (biography on George Washington Carver), The Reason for a Flower by Ruth Heller, Let’s Read and Find Out Science series (these have levels 1, 2, 3), Take-Along Guides (we have Tracks, Scats and Signs and Birds, Nests and Eggs), Dem Bones, The Cloud Book by Tomie de Paola, Pompeii…buried Alive, Detectives in Togas, or Paddle to the SEa?