Clothes

Comfortable loose-fitting clothing
Slipper socks
Change of underwear
Eyemask & earbuds
Loosing clothing to return home in (crucial)

Hygiene

Feminine friendly wipes
Travel deoderant
Sanitary pads & panty liners 
Hairbrush
Toothbrush & toothpaste

Keeping Busy

Headphones
Portable tablet
Colouring/reading books
Magazines
Don’t forget your chargers!

Snacks

Ginger, peppermint, or chamomile tea
Non-dairy protein bars or popcorn
Dark chocolate
Bananas
Nuts or mixed trail

Pre-assessment

You’ll always have a pre-assessment with your surgeon, this will determine the exact length and objective of the surgery, and whether you’ll be under general anesthetic (this can vary depending on the severity of your condition).

Endometriosis Specialist Joanne Hanley on Endo.org offers a little more detail here.