There is no one specific transformer that is best for fractal burning. The type of transformer you need will depend on the kind of welder you are using.
For example, if you are using an oxy-acetylene welder, you will need an oxygen cylinder and an acetylene tank. These tanks can be purchased at most hardware stores.
If you are using a plasma arc welder, you will need a power supply that can provide enough electricity to run the welder. These supplies can be found at most welding supply stores.
No matter what type of welder you are using, it’s important to make sure that the transformer is properly rated for the amperage you need.