Here are the work trays my three and five year old have been choosing recently. Inspiration from montessori books and montessori inspired blogs, in particular playing house in maryland blog. These also work wonderful at preschool. As children arrive in the morning, have trays set up for them to choose. Then after a designated period everyone moves right until all have had a turn with each tray.
Make sure to have child start from the top left and work right for reading readiness.