I know a couple videos based on Fairies like the type of fairy's and how to locate them. As for dragons , I know a video about the Draconic path if you would like that. I'll link the videos, please keep in mind these videos may or may not help you they did help me.Sorry, I'm not really familiar with HellHounds maybe someone else can help you with that.
Stuff about the hellhound just in case Google doesn't tell you.
1.) if you see a hellhound and if you tell another person that person will die
2.) there is a belief that hellhounds are the devil's pet. If you made a deal with the devil (in this belief its your soul). The devil would send his hellhounds to get your soul or just make your life a living hell.
I only know about Hellhounds through paranormal investigating. Apparently they come as black dogs and if you see them, they're an omen of death. Either you or someone you know will die. Some have red eyes. In all cases I've heard, they're considered bad luck.