I don’t know about word processors, but, in HTML. you’re supposed to define filigrees or flourishes as images. You can even handle them in the CSS to make them paragraph separators (or, better yet, replace the horizontal rule <hr> which is uaully used for this purpose) HTML specifications don’t support using non-alphanumeric fonts, and standard fonts don’t include these symbols.
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Of course, the above is another way to pull it off. Too bad vbulletin doesn’t support [hr].
In Project Gutenberg and Distributed Proofreading, that is called a thought break.
There are many symbols used by typesetters to mark this, from a line of asterisks to ornate flowing lines.
I don’t think a fictional Gaulish warrior has got anything to do with this. 
In most standard book publishing, the art director creates a paragraph separator. In the past these were created by hand. They still might be. I don’t know if there are professional tool banks that have these to license, though I wouldn’t be surprised.
But you will simply not find very many of these in webdings (named for the Zapf dingbats) or any standard font or supplement in a word processor. They are a professional tool and most art directors would be insulted if you thought they took them out of Word.
With the manuscripts I worked with once or twice (freelancing for a major publisher), the raw doc indeed came from the author(s) in Word format. From there I marked it up with special formatting codes and sent it off to be imported into something else – Quark or InDesign, I suppose, which are much more advanced publishing and layout tools than Word. That’s when it goes from just 300 pages of straight text to actually being formatted like a book. I assume this is where the actual symbols get inserted, rather than just some placeholder. It’s definitely an art or design decision what kind of symbols to use, so those are the tools that would be used to create/insert them.
That said, you can insert any image you would like into a Word document, if no available font has a pleasing aesthetic for you.
Or you could just Insert…Symbol - from where you can choose from a wide range of symbols and select from different fonts. Insert one or many, and then you can centre them across the page as you would standard text.