"Show gear" is all of the things that you'll be taking to the show to make sure that your cat is well taken care of in both the show hall and hotel (should you be staying over) and will also make her more comfortable. This also includes all of your grooming items, cat food, water...and you might need a item or two for you as well!
Your show gear can be as minimal or involved as you wish. And you may take various items depending on if you are driving or flying to a show. (yes, many people do fly with their cats to long distance shows). Longhair cats require more gear than shorthair cats just due to the nature of maintaining a long coat for the show ring. (think shampoos, combs, and blow dryers for those baths in the hotel room very early in the morning).
You may also find that you have enough gear that you find it easier to haul your cat and gear on a luggage handcart. Other people have made trolleys from two pieces of plywood, each covered on one side with carpet or material. The bottom piece had casters on the bottom and a pull. Then, place your cats' carriers on top of it, and finally the other covered piece of plywood. The two pieces of plywood stay together with bungee cords connected to eyescrews on each. In the show hall, you can cover this with a sheet and it's a grooming stand.
Obviously, it will take a lot of experimentation to discover what works best for your situation.