Let's see... excluding Quinn's puppy collars (which I keep because they're cute), she has
1 Braid-a-roo tag collar that she wears all the time
3 Ella's Lead collars
2 Collarmania collars
1 Collar Shop martingale
1 Lupine martingale
1 damask print - can't remember brand
1 Browning biothane collar
1 Weaver leather collar
1 Rogz nylon collar
I think that's it - I may be forgetting one or two. But assuming I got all of them, that's 12 collars for one dog.
Leashes I am slightly better with - 2 Pacos, 1 Weaver, 4 nylons, and 2 slips. Total 9. Oh, and two long lines. I only use my leather ones or the long lines - the nylon ones I all got free (or at least <$2) and I only use when my leash is going to get wet/dirty. And I have one brand new in a consignment shop, but since I don't want it I don't count it!
She has two harnesses (one Kong, one Hurtta).