I first came across a reference to freezer paper when trying to follow a tutorial I found on pinterest a few years ago. Most things from the US have some sort of UK equivalent, except freezer paper it would seem and I could not find it anywhere! Originally intended for wrapping food for the freezer, crafters and quilters soon found other uses for this versatile paper and now it even contains a reference and instructions for certain craft applications on the box.
It would be easy to assume that it is very similar to greaseproof paper that is readily available in all supermarkets in the UK but it has a very different quality. Rather than having a single waxed side, freezer paper has a plastic coated side which, when ironed to fabric, sticks to it and stabilises it but leaving no residue when removed. The other side is white paper which allows designs to be drawn on in the same way you might use bondaweb for making appliques.
However, freezer paper has many more uses. By stabilising the fabric, it allows fabric to be printed on in inkjet printers, it stops tricky jerseys from curling making it far easier to cut, it reduces the number of pins required when using delicate fabrics and is great for creating templates in quilting as once the template is cut out, the paper will restick several times saving massive amounts of time at the cutting table.