I'm not sure exactly what your strategy is, but here is my list of sites for each strategy. I'm currently rent-by-rooming, so I haven't used all the sites listed. I just compiled this list for whenever I do use another strategy.
Traditional Long Term Rental: - Zillow - Realtor.com - Hotpads - FB Marketplace - FB Groups - Apartments.com - Craigslist
If you are looking to stay away from the 3 you mention (Craigslist, Airbnb, or FB Marketplace) I would post that you have a room for rent all over your social media accounts. In my experience when renting out rooms, referrals are going to be your most reliable bet.