There are several types of drills used for drilling metal, including:

1. Twist drill: This is the most commonly used drill for metal and is used for drilling holes in a variety of materials including wood, plastic, and metal.

2. Spade drill: Also known as a paddle drill, this type of drill is designed for drilling large holes in soft materials like wood and plastic.

3. Spot drill: This type of drill is used for starting a hole and helping to prevent the drill from wandering while it is in the material.

4. Center drill: This drill is used for creating a starting point in the center of a workpiece, where a larger drill can be used to create the final hole.

5. Step drill: This type of drill is designed for drilling a range of hole sizes in one operation.

6. Taper shank drill: This drill is used for heavy duty drilling and is commonly used in drilling large holes in metal.

7. Cobalt drill: This type of drill is made from a high-speed steel that is coated with cobalt, making it more durable and suitable for drilling harder materials.

8. Carbide drill: This type of drill is made from tungsten carbide and is suitable for drilling materials like cast iron, stainless steel, and hardened steel.

The type of drill used for drilling metal will depend on the specific material being drilled and the desired size and finish of the hole.