One great Percy Frozen fanfiction is 'Percy in Arendelle' where Percy somehow gets transported to the world of Frozen. It has an interesting plot as Percy tries to adapt to the cold climate and the new magic system while also befriending Elsa and Anna. The author does a great job of mixing the two universes.
One great piece of httyd and frozen fanfiction is 'A Dragon's Adventure in Arendelle'. It combines the magic of the dragons from httyd with the icy world of Frozen. The story has Toothless befriending Elsa and they go on a journey to save both Berk and Arendelle from a common threat.
There are many on various fanfiction platforms. Some explore the idea of a vampire being trapped in the frozen world, like in a story where a vampire is accidentally transported to the 'Frozen' universe and has to adapt to the cold and deal with the magical elements while hiding his true nature from the locals. It makes for an exciting read as it blends two very different concepts.
Well, 'The Enchanted Elsa' is a fanfiction that I like. It tells the story of Elsa being enchanted by a dark force and how she overcomes it with the help of her friends and her own strength. There's 'Elsa: The Protector' which shows Elsa as the protector of Arendelle not just from physical threats but also from magical ones. And then there's 'Elsa's Dream Adventure' where Elsa goes on an adventure in her dreams and has to find a way to bring back something important from the dream world to the real world.
I'm not aware of any specific 'frozen lemon fanfiction' that I can recommend off - hand. Since 'lemon' often has a bit of a risque connotation in fanfiction, it's important to be cautious when looking for such works. You could try searching on some well - known fanfiction websites and filtering through the results based on your preferences, but make sure to abide by the website's terms and conditions.
One interesting Naruto Frozen fanfiction could be 'Naruto in Arendelle'. In this story, Naruto might use his ninja skills in the Frozen world. For example, his shadow clone jutsu could be used in creative ways to deal with the challenges in Arendelle, like helping to build things or defend the kingdom.
I'm not sure about specific frozen lemons fanfiction titles off the top of my head. But you can start by looking on popular fanfiction websites. Check the reviews and ratings of the Frozen - related fanfictions there. Usually, the ones with high ratings and positive reviews are worth reading.
There's also 'Frozen in the Wizarding World'. In this fanfic, the Frozen characters find themselves in the middle of the Harry Potter universe. It details how they adapt to the new magical environment, with Anna making friends with the Gryffindors and Kristoff being fascinated by the magical creatures. It's a really fun read as it plays with the different magical concepts from both franchises.
There's also 'Frozen Fox and the Hidden Leaf Mysteries'. In this fanfiction, the frozen fox is a new addition to the Hidden Leaf Village. It brings a new set of challenges and adventures as the villagers try to understand and work with this unique creature. The story is full of action and mystery, with the fox's powers being a central focus.
There are 'pregnant Elsa Frozen fanfiction' stories that take a more adventurous turn. Elsa might find herself in a situation where her pregnancy is at risk due to some external threat. It could be a new villain who wants to use her unborn child for some dark purpose. In these stories, Elsa has to not only protect herself but also her unborn baby while still maintaining the balance of Arendelle. The other characters like Kristoff and Sven might also play important roles in helping Elsa during this difficult time.
There are often fanfictions where the Guardians from rotg come to protect Arendelle from some new threat. For example, Pitch Black could be plotting to take over Arendelle, and the Guardians team up with the Frozen characters to stop him. You can find these on various fanfiction websites like Archive of Our Own (AO3).