2ft x 2ft reflectix that triples as my doorstep, my sitpad, and a suppliment to my UQ if needed. Plus, it works really well to fan a stubborn fire to breath some life into it.
I'm in that 2-3foot range of tyvek. Noticed at MAHHA that WV's actually said 'Welcome', how cool is that!
When I use one, it's my poncho (so, about 3.5' x 5'). I put my shoes and ditty bag on it; that seems to keep the thing in place just fine. Wrap the leading edge over the tops of everything if it looks like rain, just like Duffy does.
"Just prepare what you can and enjoy the rest."
I use the Walmart 5'x7' backpacking tarp. It's big, but my dog comes with me and I'd like to keep him off the ground, so his bed and my shoes, pack, and other random stuff all stay on the tarp as well. If it rains, the only thing that gets wet/dirty is that one piece of gear, and not something else that I use for multiple purposes.
I use an old tent foot print that I soaked in permethrin for obvious reasons, keeps little things away with gear and shoes on it, but several years ago went to gear hammock as an unplanned rain washed gear into a creek, ( if you remember seeing vids from Colorado hang i think earlier this year, you'll know what kind of storm it was), plus when I've had to go to ground in biv the treated ground cloth has helped (a lot) in keeping pest off. Found the few oz's was easier than losing gear, IMHO, jim
Half of a car sun screen. Doubles as a sit pad when hiking.
I use my Zpack's cuben rain kilt. I sewed loops in the corners and use sticks on sight to stake it down. I put my Gossamer Gear sleep lite pad on it from my back pack for my dog to sleep on. I hang my pack on the hammock at the foot end.