HSS Twist Drill Bits

Long twist drill bits are designed for drilling holes which run deeper than a standard-length drill bit. A typical example might include installing security latches on a door, which would require drilling down through the ends of the workpiece to a depth of up to one foot.
An especially long twist drill bit will be required to complete everyday tasks such as these, but the main potential disadvantage of an extra-long drill bit is that it can tend to wander more as it goes. Longer twist bits are also more prone to breaking at lower gauges than short bits, particularly when more force is applied to get through greater depths of material. Twist drill bits are also available in a short form.

Reverse twist drill bits are designed to work with your drill set to the reverse rotation direction (counter-clockwise). However, unlike a standard drill bit which would simply drag its cutting edge backwards around the interior of the hole with the drill running backwards, reverse twist drill bits are machined with their fluted cutting surfaces facing in the opposite direction.
When a reverse bit is inserted into a chuck and the drill is run counter-clockwise, this means that the bit performs the same sort of cutting action that a standard drill bit does when moving clockwise. This can be extremely useful as a method of screw extraction when the slots on a screw head have been worn away.

The vast majority of twist drill bits are made from high grade steel, of which two particular formulations are especially common for specific scenarios:
High-speed steel (HSS):
High-speed twist bits are effectively a universal type of drill bit, and most types of HSS twist bits will be suitable for general drilling work
HSS twist bits are a requirement for drilling through various sorts of metallic workpieces and surfaces, as they are formulated to withstand the higher temperatures generated through the increased friction involved in drilling metal without losing hardness (temper)
Carbon steel:
Conversely, if you are only going to be drilling through wood, you can instead opt for a carbon steel twist drill bit.
Carbon steel twist bits tend to be less flexible and more prone to breaking under higher torque forces and temperatures than HSS versions, but drilling most types of wood and composite lumber materials is unlikely to cause this issue.
Although more brittle and less robust than HSS bits, especially under higher working temperatures, carbon steel twist drill bits can prove a more cost-effective option for exclusively wood-based drilling applications.

If you need to drill into metal, you can't typically expect to use a regular steel or carbon steel drill bit designed for cutting through wood. This is especially apparent when dealing with particularly hard materials and surfaces, such as steel. However, there is a good range of treated, coated and tipped twist drill bits for metal, all of which are manufactured to offer a more robust cutting tool for tackling those tougher metalworking jobs.
The most widely available include titanium twist drill bits and cobalt drill bits. Like regular high-speed steel (HSS) drill bits, these are expressly built for the purposes of drilling through metals. The key difference between titanium and cobalt drill bits is that the titanium versions are toughened with a titanium oxide (or titanium nitride, also known as TiN drill bits) coating, while cobalt steel twist drill bits are crafted entirely from solid cobalt steel.