In the summer I came across a Four loop Mossy Oak Lanyard which is designed for carrying calls.

However if you cut the stitching and remove the alluminium collet it becomes a carrying strap with 2 nooses at each end. You then just open up the nooses, slip over the roe/munty legs to the knee joint and pull tight. Simple and effective carry strap.

Cost 8.69p

Occupies little space in the pocket and handy for all sorts of things