I have a few I've never shot, but they were all used by their prior owners. Some are old milsurp warhorses that I either don't have ammo to feed to them, I haven't taken the time to learn how to operate them, or I simply haven't been to a long enough range often enough to get them into the mix. Those I really don't mind not shooting. Their value to me is in the stories they tell. I'm definitely a collector vs. a shooter with the WW2 stuff.
I do have one modern rifle (7.62x39 AK) still NIB. I got a good price from a trusted member here so I grabbed it and put it away. I have another "better" AK I shoot. I guess the NIB one is squirreled away for EOTWAWKI or if AK prices go nuts then I can turn some cash.
I have a few that have had very few rounds through them. I built an AR pistol with my TGO upper and lower from the group buy a few years ago because pistols were kind of the hot thing at the time. I'm not sure I put a full 30 round mag through it. I prefer the 16.5" or longer ARs so it sits and does nothing. Same with an AK pistol. I got a Mini Draco years ago and was planning to SBR it, but never took the NFA plunge. I know I didn't get a whole 30-rd mag through it. It's kind of fun to shoot, but I'm not accurate with it so it too stays tucked away for "maybe someday I'll do something with it". My Mosins (1891/30 and an M44 carbine) are kind of like them too. I know they've had a lot of rounds sent through them by Soviet troops, but not by me. They're a hoot for a few rounds down range and to watch the huge fireballs from the M44 but then that's enough. I keep them "just because".