I do one set of good quality stuff for each kid from LL Bean or other good brand (sometimes I'll check out REI, smart wool, Reima, etc. for sales). This is what we use for outdoor sports and hiking and anything where I go with my kids the whole time and can make sure they don't get left behind somewhere.
Then I buy sets of cheaper hats and mittens on Amazon and these go to school and get tucked into jacket pockets for the playground. Also good to take for travel or to have extras on hand in case friends or cousins are over and need something.
I used to try and buy the middle ground options and encourage my kids to keep track of them. It was futile. Our elementary school has kids transition all day long, for different "blocks" with different teachers as well as lunch and recess. It's honestly a miracle that we've never lost a coat, lunchbox, or even water bottle (misplaced all but they find their way back to us). Anything else just disappears into the ether. Falls out of pockets, gets mixed up with someone else's stuff, winds up stuck behind something on the playground, etc. It's not worth it to try and keep track.