What are some of the best supernatural crossover fanfiction?

The best crossovers often explore the different power dynamics. Supergirl's super strength and flight compared to the Winchesters' hunting skills and knowledge of the occult make for an interesting mix. There are fanfictions where they exchange knowledge, like Supergirl learning about ancient spells from the Winchesters and the brothers getting tips on how to take down powerful foes from Supergirl.

One great Merlin - Supernatural crossover fanfic is 'The Hunter and the Warlock'. It combines the magic of Merlin's world with the demon - hunting aspect of Supernatural in a really interesting way. The characters from both shows interact in a believable manner, making for an exciting read.

I really like 'Crossroads of Krypton and the Hunting Life'. In this fanfiction, the writers did an amazing job of bringing in the mythology of Smallville and Supernatural. Dean and Sam Winchester end up in Smallville and get involved with Clark's world. It's full of action and some really cool character moments. It shows how the different powers and skills of the characters from both shows can work together or clash in interesting situations.

I really liked 'When Hunters Meet Slayers'. It's a well - written fanfic that does a good job of melding the two universes. It has some great action scenes where Sam uses his research skills to help Buffy and her gang figure out a new type of demon that has emerged, which is a combination of a demon from 'Supernatural' and one from 'Buffy'.

One great Supernatural and NCIS crossover fanfiction is 'The Hunt in Quantico'. It combines the mystery-solving aspect of NCIS with the supernatural elements of Supernatural really well. The characters from both shows interact in a very believable way, and the plot keeps you on the edge of your seat.

One idea could be a story where a werewolf from the werewolf lore gets caught in the middle of a Supernatural's Winchester brothers' hunt. Maybe the werewolf has information about a powerful demon they are chasing.

A popular one is 'Crossing Paths'. This fanfiction has an interesting take on the crossover. It starts with a mystery that involves both the Supernatural and Buffy universes. The author does a great job of writing the characters true to their original personalities. Buffy's determination and the Winchesters' tough - guy attitudes are on full display, and the story builds up to a very satisfying climax.

One great 'Supernatural' and 'Arrow' crossover fanfiction is 'The Hunt in Starling City'. It combines the dark, supernatural elements of 'Supernatural' with the gritty, urban setting of 'Arrow'. The story has Dean and Sam Winchester arriving in Starling City to hunt a demon that's been causing chaos in the criminal underworld, which draws the attention of Oliver Queen and his team. They initially clash but then realize they need to work together to stop the greater evil.

Well, there's 'Parallel Encounters'. In this fanfic, the settings of Supernatural and Tramiplier are merged in a really interesting way. It starts with a character from Tramiplier accidentally stumbling into the world of Supernatural. The story then unfolds as they try to find their way back while getting involved in the ongoing battles against demons and other evils in the Supernatural realm. It's full of action and some really cool character interactions.

Another great concept is a crossover where Eleven's powers are mistaken for some kind of witchcraft by the Supernatural universe. Sam and Dean initially think she's a threat but then realize she's actually a powerful ally against a common enemy. They could be facing a powerful being that can manipulate time and space, and Eleven's telekinetic and telepathic abilities are crucial in defeating it.