Sensory mats - "Goo bags - recipe for goo. I've had it suggested to use an entire bottle of dollar store hair gel, but this is probably just as inexpensive, and you can make whatever VIBRANT colours you want." Letter writing with fingers or Q-tips.
Print baby clothes sizes on paper/cardstock & stick inside clear bin for easy identification (labels won't fall off) in storage. Colour coordinate the labels according to gender. - Great idea for any home storage boxes (Seasonal, Keepsakes, etc)