One of the most important things I bring other than the camera itself. I've seen others carry their cameras on straps, however a backpack is easier for me as it can carry other items that I might need.
Camera Bag
Living in Florida, it's rains so often, so I got a lens hood for both my long lens and my short. It has honestly saved my lens from water droplets while I shoot in the rain.
Reversible Lens Hood Shade Protector
Just like the one for my long lens, I went ahead and grabbed one for my other lens as well.
18-55mm Lens Hood Shade
A must have for taking pictures with a bright sun. There are awful glares on the cars and can ruin the photos you take. Plus, a polarizer will protect your camera lens from any small debris. It's cheaper to replace a polarizer rather than a whole len...
Circular Polarizer Camera Lens Filter
EXTRA. SD. CARDS. I cannot count the amount of times I've forgotton my SD cards at home. These Sandisk ones are my favorites.
SanDisk 128GB
I like to edit on the go as well as empty my SD cards. Not needed but a option.
Toshiba Canvio Basics 2TB Portable HDD
Extra items
The amount of times I've had to use my shirt to wipe my lens because I didn't have lens wipes in my bag was insane. I like to have a cleaning cloth in my pocket for quick wipes and the things for a deeper cleaning in my backpack for after the race.
Altura Photo Cleaning Kit
One of the MOST IMPORTANT things in my opinion. You need to protect your ears. These cars are loud, though they might not seem like it. They. Are. Loud. Don't be stupid. Get earplugs.
VIBES Ear Plugs
It can get cold just like it can get hot. Especially at 24 hour races, it gets cold at night. These things seriously saved my fingers.
HotHands Hand Warmer
It can get pretty hot sometimes with no long breaks, so I bought myself a handheld fan, and it is a lifesaver.
Portable Handheld Fan
Not needed, but I like how it's compact and I can easily slip it into my backpack and edit on the go.
Apple iPad 10th Generation
Again, completely not needed, but it does make editing a lot easier (at least for me).