Mascara especially the water proof so that you do not have a messy face incase it rains or you get youself in a situation where tears will be shed
Make up brushes of various sizes to create the day and night look for different occassions and times of the day.
Lip gloss. Carry it during the hot days when you do not have the time to reapply your make up. Dab a few layers on your lips to bring back the shine.