Every six months or so, when I remember, I get out the three ammo boxes I store my batteries in and charge them all. I also usually recycle a few which are worn out.
I was struck this time by the batteries I don’t use any more.
I have even forgotten which lights I bought some of them for, so I made a list;
10180
10440
14500
26350
14500
16340
18350
18650
26650
17670
18500
20700
21700
75175
I probably also have some tiny batteries in stored lights which are not on the list.
Madness really but it’s a hobby.
I’m sure some of you have a larger variety, would anyone like to list them?
One more, several less.
10180, 10250, 10440, 16340, 18350, 18650, 21700, 26650.
I have a battery tube for 10280 but no battery of this size.
Added: 26350 as well
For the past few years, I have only gotten flashlights that take AAA, AA, or 18650 cells.
I don't fiddle with the other types of batteries anymore.
Eventually, I'll probably get a 21700 flashlight if one really appeals to me.
Thanks for making me aware I’ll have to try harder 
10180, 10440, 14500, 18350, 18650, 21700, 26350, 26650, and lots of AAA-primaries.
I’m just old enough to remember buying A and B batteries at a local radio & electronics store.
I used batteries like these to power a couple of home made tube radios. This was around 1970-72. They were already obsolete. Store still had the parts sitting around.
I also used these old style A batteries to heat the glow plug on Cox .049 engines.
The no 6 battery lives on in Alkaline form!!!
Wikipedia doesn’t even list 26350. I like that format for D4S and SC26. 
‘Fitorch’ and Imalent both make 26350 batteries, it’s one of my favourite sizes for my big stumpy hands!
A lot of the more obscure sizes are AW batteries- his used to be the ‘go to’ batteries when I first became a light nut but I don’t know if he still supplies them.
I use 10180, 10440, 14500, 16340, 18350, 18650, 21700, 26350 and 26650. I would like a couple quality 10180 and 10440 spares, and will look for them. I also really like the 26350, built an XHP50.2 that uses a pair of them to keep the length down, one of my favorite handy throwers. I have not tried the tubes for the 26650 Emisar lights, but suspect that I might like them. My wife uses one in an SC26(?) with a short tube. I remember as a kid seeing the old dry cells forsale, used in fence chargers and cattle prods and yes, even big bulky maybe 80 to 100 lumen lights.