Rope and Climbing Gear: Unless vertical caving is planned, ropes and specifically climbing gear are not necessary. However, if drops exist, it might be a good idea to bring a hand line in order to help people over drops or steep slopes.
Helmet: I once heard a stupid person say, "wear a helmet so if the cave collapses on you, you'll survive". Hello!! Let a bunch of rocks fall on your head even with a helmet on and you are still dead meat. The fact is, wear a helmet so you don't bump your head on cave walls and ceilings. Trust me, it can hurt!
Suits: Coverall style suits can be helpful, especially when caves are cold and wet. These suits also help protect the wearer from cuts and scratches.
First aid kit, food, etc.: I always find that having these things, atleast in a backpack or outside of the cave, can be very helpful. You never know when you will need them. They could save your life. Most importantly, drink lots of water because you sweat most of it back out.
For more information on gear, go to:
Karst Sports