The choice of the best metal for a knife depends on various factors, including the intended use, desired properties, and personal preferences. Here are a few popular metals commonly used for knife blades:

1. Stainless Steel: Stainless steel is a popular choice for knife blades due to its excellent corrosion resistance and ease of maintenance. It comes in various grades, such as 440C, VG-10, and S30V, each offering different levels of corrosion resistance, edge retention, and toughness.
2. High Carbon Steel: High carbon steels, such as 1095, are known for their excellent edge retention, hardness, and durability. They can be sharpened to a very fine edge and are well-suited for applications where edge retention is crucial, such as hunting or outdoor knives.
3. Tool Steel: Tool steels, such as D2, A2, and M390, are known for their exceptional hardness, wear resistance, and toughness. They are often used in the production of high-performance knives that require durability and edge retention.
4. Damascus Steel: Damascus steel is a combination of multiple layers of different steels forged together to create a unique pattern and exceptional aesthetics. Damascus blades can have good overall performance, combining hardness, toughness, and sharpness.
5. Ceramic: Ceramic blades offer excellent hardness, corrosion resistance, and edge retention. They are highly resistant to wear and do not require frequent sharpening. However, ceramic blades are brittle and can be prone to chipping or breaking if subjected to impact or lateral stress.

Ultimately, the best metal for a knife depends on the specific requirements of the intended use. Consider factors such as corrosion resistance, edge retention, toughness, ease of sharpening, and overall durability when selecting the metal for your knife. It's also important to consider the heat treatment, craftsmanship, and quality of the blade in addition to the chosen metal.