Maybe you don't have it. Maybe you are incredibly organised and don't need the category. Maybe you are happy-go-lucky and there's an awful lot of it in your budget.
I call it WIGIG. When it's gone it's gone. It's the money which I set side for miscellaneous purchases. This month I've bought key chains, the Highway Code, a few pamper-type toiletries, a Sudoku book, a screwdriver among other things.
For some its WAM - walking about money. For others its Miscellaneous.
But what do you call it? I'm curious.