Good question! You really don’t need to bring anything but yourself! That being said, and to add some variety (and personality!) to your session portfolio, I strongly encourage you to bring certain things and happily welcome the use of props! Below is a list of recommended ideas for things to have handy at your photo session.
Water (seriously, have it handy)
Small mirror to check your hair/makeup
Comb/hairbrush
Sunglasses
Prop jewelry (flashy necklace, watch, etc)
Hat
Shawl/scarf
Blanket to sit on
Bouquet of flowers
Custom announcement sign
Bubbles
Balloons
Color smoke
Biodegradable confetti