Sophia Institute's K-8 catechism text Spirit of Truth is now available in a completely digital format. This is not an ebook. This is a fully interactive experience.
https://sophiainstituteforteachers.org/COVID19CatechistSupport#virtualclass

Not using Sophia's catechism curriculum? You can still use any of their free resource to supplement your lessons. Click on the Lesson Plans tab to view the dropdown menu of free resources.  https://sophiainstituteforteachers.org/elesson/teaching-the-liturgical-year