I really don't think those are cowbells. Cowbells are usually made of copper and they are square. Are those silver? They may be worth something, I'd investigate 'em a little if I were you.
Those top three are bells that are rung by hand, pushing open a door etc...The only thing I know them as are bells...The other round ones I think are called crotal bells (sleigh bells). I've read that the more irregularly shaped they are, the older they are and most likely the more valuable. Don't quote me though. I'm no bell expert. Here's a link. Some of them can be worth quite a bit, but I think most are not worth much...