If you've seen horizontal separators on hubs (and I have older hubs with some) - what those actually are - are picture capsules, and the picture is just the separator.
I'd give you the link for a site that has a lot of those....but I'd have to dig through a thousand emails to find it.
They typically don't belong to anyone, so ...I'd just download one and use it were I you.
I'll give you an example of one on my own hubs, and if you see one on any of my hubs - then please feel free to use it, you can just hit "copy image," or you can download it. The one's I've been using are typically herringbone pattern.