Ever wanted an extra pegging point on your flysheet? You could sew a loop, but it is much easier to use a Holdon Tent Clip. They weigh 11g each and they can be positioned wherever you need them. I carry a couple for my Duomid. They help to tame the flapping of the long back wall.
I’ve also used them to rig up a shock cord retainer on my POE sleeping mats to stop the pillow falling off the end of the mat. They cost 55p each (or less if you order in quantity) from UK Tarps.
If you are a tarp user, they could be useful as well. A very simple but effective bit of kit.