You can find various parts of the Barashkova grammar series—including the (Exercise Book) and the Kniga dlya Roditelei (Parent's Book)—on several educational resource sites:
If you finish Barashkova and want more, these world-class resources offer free exercises and explanations: You can find various parts of the Barashkova
Great for learning grammar through short videos and podcasts. You can find various parts of the Barashkova
Interactive grammar lessons for A1–C1 levels. You can find various parts of the Barashkova