The choice of the best metal for a sword depends on various factors, including the intended purpose of the sword, the desired characteristics, and the preferences of the swordsmith or user. Different types of steel and other alloys have been used historically and in modern times to create high-quality sword blades. Here are a few examples:

1. High Carbon Steel: High carbon steel, such as 1095 or 5160, is a commonly used material for sword blades. It offers a balance of hardness and toughness, allowing the sword to hold a sharp edge while remaining resilient and resistant to deformation.
2. Tool Steel: Tool steels, like T10 or S7, are known for their exceptional durability and resistance to wear. They are often used in the production of cutting tools and can be suitable for swords requiring high impact resistance.
3. Stainless Steel: Stainless steel is corrosion-resistant and requires less maintenance compared to carbon steels. However, it can be more challenging to forge and may not possess the same level of edge retention or toughness as high carbon steels.
4. Damascus Steel: Damascus steel is renowned for its unique patterns and is created through a process of forge welding and folding layers of different steels. It combines the properties of the steels used in the layering process, resulting in a blade with excellent aesthetics and performance.

Ultimately, the best metal for a sword depends on the specific requirements, such as intended use, durability, flexibility, sharpness, and the preferences of the swordsmith or user. Skilled swordsmiths consider these factors to select the most appropriate steel or alloy that meets the desired characteristics for the intended sword.