There are several materials that can be used for carving foam, including:

1. Styrofoam: This is a type of extruded polystyrene foam that is commonly used in packaging materials. It is lightweight and easy to carve, making it a popular choice for foam carving projects.
2. Polyurethane foam: This type of foam is often used in upholstery and cushioning applications. It can be carved using a variety of tools, including hot wire cutters, knives, and saws.
3. Expanded polystyrene foam (EPS): EPS foam is similar to Styrofoam, but it is made using a different manufacturing process. It is commonly used in insulation and packaging materials, and it is easy to carve using hot wire cutters and other tools.
4. High-density foam: This type of foam is often used in the construction industry as insulation and soundproofing material. It can be carved using a variety of tools, including saws, knives, and hot wire cutters.
5. Floral foam: This is a type of foam that is used in the floral industry to hold flower arrangements in place. It can be carved using knives and other cutting tools, but it is not as durable as some of the other foam materials mentioned above.

When choosing a foam material for carving, it’s important to consider the project you’re working on and the tools you’ll be using to carve the foam. Some foam materials may be more suitable for certain projects or require specific tools to carve effectively.