As you probably have guessed, there are literally Thousands of nets around the world that deal with almost any topic you can think of... yes even "THOSE" types of topics. A good start to searching for HF nets can be found here:
http://www.ac6v.com/nets.htm but that is not the only source. Google can be your best friend in searching for a specific net topic...
good luck finding a niche in which to fit.
Just thought I'd mention a "no-brainer".... be sure to SCROLL DOWN the page at the above site. don't just read the BOLD print and move on... scroll down.