The following has worked quite well for me. I hate using a centered
"* *
*" for a thematic break so I use a fleuron. I write fiction, not
math-filled academic-journal articles or textbooks so this may not be
applicable in your case.
First, I use one of many available "dingbat" fonts to provide the
fleuron. I am partial to the curly-ques in Nymphette (a
readily-available free font) but there are many others.
In my preamble I define:
\definefont[FleuronFont] [nymphette sa 1.5]
Then where I want to place a fleuron I can do something like this.
\midaligned{{\MedBlue \FleuronFont g}}
In this case, the text letter 'g' corresponds to the particular
little
symbol I want.
YMMV
Take a look at the fancybreak module: