A vampire hunter from Europe who comes to America to help Lincoln. This character could have different techniques and weapons for slaying vampires, and there could be some conflict between their European methods and Lincoln's more improvised style at first, but then they learn from each other and become a great team against the vampires.
One idea could be that Lincoln discovers a hidden vampire lair beneath the White House. He has to battle the ancient vampires there while also trying to keep his vampire - slaying activities a secret from his political allies.
There might also be some original characters created specifically for the fanfiction. These could be other humans who know about Lincoln's secret or other supernatural beings that are related to the vampire lore in the story.
Definitely a magical gnome. Gnomes are often associated with magic and mischief, and they could interact with the little vampire in fun ways. And an angel character would be great too. The angel could represent the good and the vampire could be on the more 'grey' side of morality, leading to some great character development moments.
Buffy herself is very interesting. She's a strong, independent girl who has to deal with both high school drama and vampire slaying. Spike is also cool. He's a vampire with a complex personality, sometimes an enemy, sometimes an ally. And Willow, Buffy's friend, is interesting too. She has her own journey with magic.
Well, Angel is really interesting. You can play with his tortured soul concept. There are so many possibilities in fanfiction, like exploring what would have happened if he had made different choices regarding his relationship with Buffy. And Faith is also a great character to write about. Her rebellious nature and her struggle with her slayer identity give a lot of room for creative stories.
In Buffy the Vampire Slayer fanfiction, there's a popular OC who is a time - traveler. This character can go back and forth in time to prevent major disasters in the supernatural realm. They are often in conflict with the natural order of things but have good intentions. There's also an OC who is a half - demon, half - fairy. This unique combination gives them powers like flight and the ability to cast illusions, which they use to aid Buffy in her battles. Additionally, an OC slayer who was trained in a secret monastery far away and has a very disciplined fighting style is quite popular.
Lucy would be a great character to include. She could help Natsu research about water dragon slayer magic. Gray could also be there, and they could have some friendly rivalries regarding the different elements. Happy would be essential as Natsu's sidekick, providing comedic relief and also helping in some tricky situations.
In a crossover with 'Attack on Titan', Eren Yeager could be an interesting addition. His determination and ability to transform into a Titan could be used in tandem with the Goblin Slayer's tactics. They could face off against goblins that have somehow made their way into the walls, or maybe even goblins that have been experimented on by the same people who created the Titans.
Definitely Spike. He has such a complex character arc in the show. His transformation from a bad - boy vampire to someone with a conscience makes him a really interesting subject for fanfiction. Writers can explore his inner thoughts and feelings more deeply. Another one is Drusilla. Her insanity and her unique relationship with Spike give a lot of room for creative writing.
I think Giles is one of the most interesting characters. He's Buffy's Watcher, guiding her in her slayer duties. He has a lot of knowledge about the supernatural. Another interesting character is Faith. She's also a slayer, but she has a much darker side compared to Buffy. And Angel, the vampire with a soul, his inner struggle between his vampire nature and his human side makes him really engaging.