Any brief search of the internet will yield dozens and dozens of packing lists. I love the layouts and lists I have found on Pinterest. They are bright and colorful. Most contain the same information and can be filtered for the type of cruise you are taking - Caribbean, Alaskan, etc.
I stumbled on Cruise Tips TV (https://www.youtube.com/user/CruiseTipsTV) and love her style and beautiful videos. She has a LOT of cruise tips and ideas. They are very well done and she has some wonderful tips, tricks, packing advice, cabin layouts, and much more.
So this is not another packing list of the everyday items, but rather a list of things that I always wish I had remembered to bring.
Flashlight - The cabins can be dark and cozy so a flashlight is very helpful at night to find your way around.
Extra USB charger - I had a cord malfunction one year and had to purchase one at twice the price. I now pack a spare.
Packing tape or duct tape - This seems like an item that would just take up extra space, however, the ONE time that a guests suitcase ripped and they still had a flight after the cruise? I was prepared!
Note cards or Thank You cards - I am always amazed by the cabin stewards and the waiters and their ability to work and serve thousands of guests each day. When I leave them an extra tip, I like to put it in a small card.
Large laundry bag (or trash bag) for dirty clothes - This is an item that I always seem to forget to bring. The cabins can get a little "stale & stinky" sometime so being able to pack up dirty laundry is a plus.
Poopouri - MUST have this item, speaking of "stale & stinky". This is essential if you are traveling with a cabin mate and want to stay on good terms.
Room Deodorizers - I have found that a few drops of essential oils or room spray can help keep your cabin fresh and sweet.
Small bungee cord - This pairs nicely with the packing tape for those unexpected rips, tears, or blowouts.