Being new here, and really appreciating how much cool stuff others share, I thought I would chime in with something I've been enjoying a lot. Pics below are of a small easy to pack "catch" I made. Catch is in quotes because it is more of a "dump" actually, dropping the ammo in the ground in front of it as often as it catches it. But still comes in handy for me.
It packs small enough it fits in the bag I carry while riding a bike to work- often through nice open spaces that are great for shooting thankfully. Grateful that I can get some nice relaxing time taking a nice ride with a chance to shoot while getting to and from work most days.
It is small enough I can take it on wilderness backpacking trips. Nice to recover practice ammo way out in the middle of nowhere.
Made from canvas painters drop cloth, cut ~2 ft wide and ~6 ft long. 1/8" nylon rope can string between tree branches, fence posts, or pieces of rebar or other detritus that one occasionally sees in the desert around town. Canvas itself can hang over fence without nylon support line. And yes, it is duct take on the cut edge of the canvas to stop the fabric from fraying- I'm not much of a sewer.
Targets like spinners and cans easily hung over nylon support rope.
Then Canvas is holding up fairly well after stopping a lot of 7/16 steel. Has lasted as long as a heavy bath towel I used previously. It does wear and I do get an occasional pass through that gives a somewhat satisfying puff of dirt behind it even when the piece of ammo is lost.
I have been thinking of treating the fabric with tent water proofer or sprayment to see about extending the life but haven't tried yet.
Looking forward to hearing suggestions to improve and see what other people use for easy to pack catches.
Sorry, pics didn't come through in original post. Can see it rolls up to be not much bigger than the slingshot that comes with it, roll ends up being about the size of a bathroom tissue roll. ~5" in diameter.