Song Playback
Record each preschool graduate singing a short graduation-themed song (see References for song ideas). Use a plastic microphone (or a real microphone, if available) and a play curtain for a "stage" area (or use a real stage, if available). Then, playback each song for the graduates and see whether the class can identify who is singing. This game encourages students to feel more comfortable with singing and with being in front of a group.
Graduation Crafts
Have the preschool graduates make their own mortar boards. They can decorate their hats however they'd like, with stickers, markers, crayons, foam shapes, glitter glue and more. These personalized hats will be perfect for them to wear during their graduation ceremony, and they can keep them as remembrances after preschool ends.
Create T-Shirts
Buy one white (cotton) T-shirt for each preschool graduate, and have the students decorate their own graduation T-shirts. They can use fabric paint to add their hand prints and fabric markers to draw. The classmates can also autograph each other's T-shirts. Another option is having the students tie-dye their own T-shirts.