Fun "books" for toddlers to look at in the bath tub are easy to make at home and can be made with drawings, family photos, magazine pictures, etc.
Glue selected pictures on cut pieces of construction paper that fit inside the plastic baggies you are using. Glue pictures on both sides of the construction paper for two-sided pages. Then sew the baggies together by sewing sew along the inner side of the zip lock. Now the book is waterproof. Have your toddler make a cover for the book and place that in a baggie as well.
There are so many variations that can be done. ABC books, farm animal books, numbers, shapes, colors, family pictures books, and on and on. They are so easy to make and little ones love helping to make the books too.