Over the years I have encountered this and that in various places. I have picked these odd things up because they were cheap and cool. I noticed the other day an unopened box of Swift Sirocco bullet. Recall seeing them at a yard sale for cheap. Had no use for them, but got them for "maybe someday" or "maybe somebody will need them". I have boxes of this sort stuff.
It's not like I asked for Woodeigh's...but if then if someone had some.410 Woodleigh's...
One other thought. The term Gun-nut often is used sarcastically and in a demeaning fashion. In truth it is is a moniker of high honor.
A true Gun-nut is a bit like a Boy Scout. When out and about, in your travels you notice odd or different brass, bullets or reloading dies, you pick them up and hold on to the them. Be Prepared, just incase in the future you find a gun to fit them. Thus you have justification to acquire that gun.
And to carry that one step forward, if some old fart, fellow gun nut come along in need of that valuable odd bit, you would be in position to help...
I've certainly picked up some bullets I'll never use. Garage sale find was a full box of Sierra 220 grain .30 caliber soft points. I loaded up 5 in my light weight 30-06.
After firing three, decided I'd never shoot those bullets ever again! The shoulder was hurting for a week.
In a trade, came by some .45 caliber bullets that are somewhere around 375 grains that I'll never shoot, but by golly, I have them.