Bubbles
Bubbles are fun for all ages. You can print your own label with the child's name, a picture or the occasion it is celebrating and glue it around the bottle to make it personalized. If you are personalizing your bubbles, use one that has a smooth surface for the label to glue on easily. These were selected for a Dora and Diego themed party.
Play Dough
Mini Play Dough are fun for almost all ages. They are about 2 inches across and 1 inch high. A couple of each color help fill a bag nicely. If you made a round sticker you could stick these on the top of the lid or make a label to go around the tub to personalize this with your child's name or birthday theme.