One common theme is Dean's struggle with his vampiric nature. He's a hunter in the show, so becoming a vampire goes against everything he believes in. Fanfictions often explore how he deals with this internal conflict.
Another option is Tumblr. There are many 'Supernatural' fan communities on Tumblr. Some bloggers share and recommend their favorite fanfictions, including those about Vampire Dean. You can follow relevant tags and blogs to discover new stories.
In fanfiction, Dean as a Prince of Hell can open up many interesting storylines. One possibility is that his character becomes darker and more conflicted. He might struggle with his newfound powers and the evil that comes with being a Prince of Hell. His relationships with Sam and Castiel would also be severely tested as they try to figure out how to deal with this new Dean.
One great aspect of Castiel and Dean in fanfiction is their dynamic. Their relationship, which is complex in the show, can be explored even further in fanfictions. Writers often delve into their unspoken bond, creating scenarios where they support each other in ways not shown in the original series. For example, some fanfictions might have them going on a road trip together just for the sake of exploring new places and having deep conversations about their pasts and futures.
In Supernatural fanfiction, Dean often has different relationships. His girlfriends can range from original characters created by the fanfic authors to characters from the show's universe in alternate scenarios. For example, some fanfictions might pair him with a hunter from another part of the world, adding new dynamics to his character as he navigates a relationship while still dealing with hunting demons and monsters.
There could be fanfictions where the witches use tickling as a form of torture or interrogation on Dean. However, Dean being Dean, he might find a way to turn the situation around. It could also be a way for the writer to explore the relationship between hunters and witches in the Supernatural universe in a more light - hearted and creative way.
Dean in Supernatural fanfiction is often depicted in various ways. He can be shown as a fearless hunter, always ready to face the supernatural threats. Writers may focus on his relationships with other characters like Sam, Cas or Bobby. His loyalty and his sense of humor are also common traits that are explored in fanfiction.
In many fanfictions, Dean as a Knight of Hell can bring a whole new dynamic to the Supernatural universe. His relationships with other characters, like Sam, would be severely tested. He could be seen as a threat by some and a potential ally by others who hope to control or redeem him.
I would say it's not common. 'Supernatural' fans usually discuss their favorite episodes, the relationships between characters like Sam and Dean, or the various supernatural creatures in the show. Fanfiction is a big part of the fandom, but this phrase seems rather odd and not something you'd hear often. Most fan talk is more about the show's official content and how it relates to the fan - created works in a more general sense.