Determining the "best" quality steel depends on the intended application and specific requirements. Different types of steel have varying properties and characteristics that make them suitable for different purposes. Here are a few notable types of steel known for their quality and commonly used in various applications:

1. Tool Steel: Tool steels, such as D2, A2, or M2, are known for their exceptional hardness, wear resistance, and ability to retain sharp edges. They are commonly used in the production of cutting tools, dies, and molds.
2. Stainless Steel: Stainless steel is valued for its corrosion resistance, durability, and aesthetic appeal. Various types of stainless steel, such as 316 or 440C, offer different levels of corrosion resistance and mechanical properties. Stainless steel is commonly used in kitchen utensils, cutlery, medical instruments, and architectural applications.
3. Carbon Steel: Carbon steels, such as 1095 or 5160, are known for their strength and ability to hold a sharp edge. They are commonly used in the production of knives, swords, and tools. Carbon steel requires proper maintenance to prevent rust and corrosion.
4. High-Speed Steel (HSS): High-speed steels, like M42 or M35, are known for their exceptional heat resistance and ability to retain hardness at high temperatures. They are widely used in cutting tools, drills, and machining applications.
5. Damascus Steel: Damascus steel, also known as pattern-welded steel, is not a specific type of steel but rather a technique involving layering and folding different steels together to create distinctive patterns. The quality of Damascus steel depends on the types of steel used, the skill of the craftsman, and the heat treatment applied.

It's worth noting that advancements in steel technology continue to occur, leading to the development of new alloys and materials with unique properties. The "best" steel ultimately depends on the specific requirements of the application, including factors such as strength, hardness, corrosion resistance, toughness, and other desired characteristics.