Fitted sheet, top sheet, blanket or comforter depending on the season. I run hotter so it's feet out and sometimes Pete gets a double blanket. We used to use a Hudson Bay blanket which has nice heft but was often too warm that left the rotation.

Fitted sheet, then a duvet cover, both flannel.  No normal sheet.  In winter, there's a down comforter in the duvet cover.  The duvet cover is hand-modified to not pull from the foot of the bed.

I'm weird.
 

My feet usually don't reach the foot of the bed, so constriction isn't an issue; it just prevents cold feet.
But when I had a smaller bed (one with headboard/footboard that my current one doesn't have), I did like sticking my feet between the mattress and footboard, so that isn't an issue for me in any case.
 

Sheet(usually fitted but some not) top sheet, two pillows although the last couple months not using either one as I've been training myself to sleep on my back again, and one or two wool blankets.

P.S. I've been wearing jeans without underwear for 40 years.

flat sheet then fitted sheet, both cotton on the mattress. (Brit-style/IKEA bed) I sleep on those covered by a summer-weight duvet in a cotton duvet cover. or on really hot nights, just the cover.  Super thin pillow (two cotton covers on it), which I often discard and sleep dead flat.  I have spare pillows of varying thickness everywhere because... well it's a huge bed and looks weird without, and sometimes bits hurt that need extra support.  Or my nose bleeds.  In winter I have a couple of small thin blankets handy in case of cold feets etc.  I sometimes wear socks, but usually they annoy the fuck out of me and get tossed while I'm trying to fall asleep.  other than that, I wear nothing  the socks is a new thing since widowhood.  prior to that, I'd just use warm bits of beest :D

(I can't remember if we went to separate duvets before or after he got sick, but most of our lives we shared the same one), I suspect before tbh, but I couldn't say for sure

 weirdo.

Jeans w/o undies? yuck.