If you are new to scuba diving there are several different aspects of scuba diving and for that you will need different types of diving gear. 
If you choose to do more than traditional open water diving you will probably need to add to your scuba gear collection.
Traditional Open Water Scuba Diving
Open water scuba diving is your entry level certification, pretty much where every scuba diver starts out. With this type of diving you will need your basic scuba diving gear, mask, fins, snorkel, regulator, tank, weights and buoyancy control device (BCD). Depending on the climate and time of the year you might also want to consider a wetsuit to keep you warm and/or for protection.
Night Diving
You will need your basic scuba diving gear. A dive light (your main torch) for safety and communication, plus a back up light in case your first light fails. As you know it does cool off in the evening so you might want to also consider some other protection to stay warm and comfortable. Surface Marker Buoys (SMB) are also needed they float on top of the surface to let the dive boat know your location.
Drift Diving
Drift diving you are using the oceans current to carry you along. People refer to this as flying because you move very quickly as you are using the oceans current to carry you. You will need your basic scuba diving gear.. along with a variety of surface marker buoys and floats with a line to tow your flag and float while diving. A Reel to keep your line neat and safe to prevent it from tangling.
FreeDiving
If you are interested in freediving you will not use basic scuba diving gear. There is gear made for freediving, it will be a little different than your basic scuba diving gear. Fins for freediving are longer to take you deeper into the water at a faster speed since you are using your lungs as your tank LOL. Mask for freediving are smaller for that reason it makes its much easier to equalize. Wetsuits for freediving are in two parts, pants that are usually waist high and a top that has a hood attached for warmth and protection against the sun.
Here are just some of the different types of diving and what scuba diving gear you will need depending on your interest.
Happy Diving!
