I had posted this list a while back, can't remember where I got it from. Hope it helps with stuff you may not have thought of.
$1 or $ 2 bills (room service grat) Room service gratuities are not included in your cruise gratuities paid.; be sure to have lots for ports
Address Labels-Luggage Tags Pre-addressed labels with your name and address for disembarkation tags
Address Labels-Postcards Save time addressing postcards for family & friends
Air Freshner/Room Scent/Pillow scent
Aloe
Anti-bacterial Wipes or Gel You may want to check the ship's CDC rating before departure.
Aspirin or other medicine
Backpack May come in handy off-ship
Band-aids
Batteries (camera batteries also)
Beach toys
Benadryl
Duffle bag for Beverages/mixers/wine
Binoculars Do not leave home without these - you never know what you'll see from deck/verandah
Bonine
Books If you think you'll have time to read
Bubblewrap For breakables purchased
Bungee cord/rope For connecting cabins
Business Cards
Cameras Digital, waterproof, and/or disposables. Buy waterproof before leaving - they're expensive on board!
Candy Bring your own for the shows or movies
Carry-on with wheels Easier if you board before staterooms open (around 1 p.m. on most ships)
CD player/CDs/iPod
Clips To keep curtains closed
Clothspins & clothesline You may be able to hang a clothesline on your verandah
Coffeemaker This is only if you are desperate for coffee all the time.
Contacts/solution/case
Cooler (soft-sided) To store sandwiches for shore excursions and airplane ride
Corkscrew If you bring on your own wine
Cutting knife For fruit you bring back to the room
Deodorant
Dishwash Soap For refillable mugs
Dramamine Or get the patch from your doctor before the trip
Dry erase board To communicate with your family
Dryer Sheets Multiple uses
Duct tape (flat pack)
Duffle bag (spare) For space for your souvenirs and purchases
DVD Player & Movies & charger
Earplugs In case you have noisy neighbors
Extension Cord or Power Strip There are few outlets in the cabin (possibly only one).
Eyewash and/or eyecup In case sand gets in the eyes
Fan - hand-held Be sure to have batteries that fit the fan
Fanny pack
Feminine needs
Film/Memory Card (spare)
Flashlight
Folder or Large Envelope Store the daily newsletters and other papers
Glasses
Glasses - reading
Glow necklaces/sticks For Pirate Night
GPS
Hairbrush/Comb
Hairdryer Cabin hairdryers are weak if you are particular about this.
Hamper - collapsable/pop-up
Highlighters Have a different color for each family member
ID holder/dry box One for each family member - or at least kids
Insect Repellent packets Surprisingly necessary if going on some shore excursions.
iPod & charger
Keep cool or "migraine ice" strips Cool down instantly
Laptop & cords Wireless internet access, daily journal, and to post quicker to boards (copy and paste daily reports)
Laundry Detergent (Disney)
Laxative, correctal/gentle
List of these tips
Lotion
Luggage Bag Pack a foldable extra luggage bag for the souvenirs and laundry.
Magnetic door sign or photo holder Helps kids find their stateroom easily
Makeup
Moisturizer/Lotion Be prepared for dry atmosphere.
Nail Clippers/Small Scissors For cutting zip ties
Night Light Plug this in your cabin bathroom
Notebook/Journal, Pens Be sure to record all of your fabulous memories on a daily basis in a journal or on a laptop
Notebook/Memo Pad To organize your daily schedules
Over-the-door Shoe Holder Alternative: sweater holder with shelves and closet hooks, shoe hanger
Papaya Enzyme Tablet or Beano Helps digest food that doesn't agree with you.
Pen - laundry pen For autographs
Pens
Permanent Marker (Sharpie)
Phone Cards (staff grats) Though cash is preferred, phone cards are nice ways to say thank you.
Pillowcases & colored Sharpies (Disney - for characters to sign)
Post-it Pad Good for leaving notes for one another or your cabin steward.
Powder
Power Strip
Prescriptions/medicines
Quarters - a roll or two Especially if need to do laundry (Disney)
Safety Pins
Scrapbook/Autograph Book Save a page opposite the autograph for the photo
Sea Bands
Sense of humor
Sewing Kit
Shampoo
Shaving Kit
Sippy Cups
Snorkeling Gear Including prescription goggles - many places do not have these available; also your vest may be better
Sports bottle/water bottle/mug
Stain Stick or Packet
Steamer
Straws
Suction cups/hooks Use for hanging wet suits or on the porthole to hang lights
Sunglasses Don't forget these
the glare off the ocean can be strong.
Sunscreen/Sunscreen spray Spray for the scalp
Swiss Army knife Do not put this in your carry-on - must be in your checked luggage.
Thank You Cards You will receive tip envelopes but these will let you leave a special message if desired.
Tissues Stateroom tissues are thin
Toothbrush/toothpaste
Tote Bag/Beach Bag/Day Bag
Trash bags For dirty laundry
Travel clock/alarm clock
Travel Iron, Steamer, or Wrinkle Spray Save on dry cleaning charges; Disney has laundry room with iron/iron board
Tums
Two-way Radios
Umbrella (Alaskan cruise)
Watch - recommend waterproof
Windex wipes To clean your verandah glass
Woolite
Wrinkle Releaser - Downy
Zip straps/ties Use for luggage that's placed in the hallway on the last night
Ziploc Bags