The most common types of 20 gauge staples are:

Regular duty:

These basic 20 gauge staples have a standard T-shaped crown and straight pins. They are the most versatile and commonly used.

Headless:

Headless 20 gauge staples are also very common. They have no crown and are used where the crown may pose an interference.

Strip crown:

Strip crown staples have a wide, flat crown instead of a T-shape. They help distribute pressure over a larger surface area.

Double crown:

Double crown staples feature two crowns at the head of the pin. They offer increased grip and holding power.

Compression staples:

These 20 gauge staples have wavy or curly legs that help compress and grip thicker materials. They are used for higher load applications.

Offset staples:

Offset staples have legs that are positioned at an angle relative to each other. They are suited for penetrating at an angle.

Wedge crown staples:

These feature a wedge-shaped crown that helps drive the staple into dense materials. They are commonly used for upholstery.

Barbed staples:

Barbed staples have small barbs along the legs which grip into materials and prevent pulling out. They are more secure.

The most regular 20 gauge staples include standard duty T-crown staples, headless staples, strip crown staples, double crown staples, compression staples, offset staples, wedge crown staples and barbed staples. Each type has features tailored for specific uses and materials.