It is definitely Angelina Fibres, or also known as Fusible Fibres. I have a whole bunch, comes in lots of different colours.You should find a lot of stuff on Pinterest/You Tube.
This panel, and these butterflies were made from it.
Quick how -to. basically you ink up your stamp in Staz-On. Then lay the stamp down, face up. Arrange the fibres over the stamp, making sure it's covered. Then cover with a sheet of greaseproof paper- I think that may be what you call deli paper?, not sure. Then Iron over the top, takes about 30 seconds. It does not damage your stamps at all. Then lift off the paper, and peel off your fused fibres.