I recently splashed out on a Thermarest  Neoair Xtherm sleeping mat (agonized over the Sea To Summit Comfort Plus Insulated due to it's inbuilt redundancy but Xtherm won on weight and R value), and as expected it skitters around my tent floor, which when combined with it being already relatively narrow makes for an unsettling nights sleep. I *also* shelled out on a Thermarest Questar bag which attaches, so at least that was one less variable, but I was still chasing my sleep around in circles.
I read that some people put lines of seam grip on the floor of their tent, but I 1. want to reseal my floor soon and that would get in the way, and 2. would prefer not to have permanent ridges on my tent. So I asked around on a free giveaway group and got my hands on some supergrip/nonslip rubber mesh material - and it works! A length under the middle of the pad has stopped it floating off where it pleases!
It's super light, can be rolled up in the mat, and is cheap (for me, free!). I might experiment with different lengths and placements for s**ts and giggles, but thought I'd pass the hack on!

Now I just need to anchor my Fillow down so *it* stops wandering (I don't think the same solution will work without glue or stitching which I'm nervous about) but any hacks on that front appreciated!

Also, any other gear-hacks out there??