One possible story could be an adventure where Gray, Lucy and Natsu team up against a powerful dark wizard. Gray could use his ice - making magic, Lucy her celestial spirits, and Natsu his fire - dragon slayer magic to overcome various obstacles and defeat the enemy.
The fanfic might also be about a friendship - building journey. Maybe they start off with some misunderstandings among them. Gray and Natsu might be bickering as usual, and Lucy has to play the mediator. As they travel together, they learn more about each other's pasts and grow closer as friends.
Well, 'The Team's Unity' is also a good one. It's all about how Lucy, Natsu, and Gray work as a team. It delves into their backstories a bit and how they've come to rely on one another. It keeps the story clean and focuses on the positive aspects of their relationships.
Well, Gray and Natsu often have a competitive dynamic. In a fanfic, this could be played up with them constantly trying to outdo each other in battles or challenges. Lucy might be caught in the middle, sometimes annoyed by their antics but also relying on them for support. For example, when facing a tough enemy, Gray and Natsu might start arguing about who gets to land the first blow, while Lucy is trying to come up with a more strategic plan using her spirits.
Well, one possible plot could be that Natsu and Lucy's relationship evolves from friendship to something more romantic. Then, an unexpected pregnancy occurs which throws their lives into chaos. They might have to face the reactions of their friends and deal with their own fears and insecurities about becoming parents.
There is a fanfiction called 'Natsu, Gray and Lucy's Unusual Day' which is quite interesting. In this story, they find themselves in a strange magical situation that they have to figure out together. It's full of mystery and the characters' personalities shine through. It shows how their different abilities and personalities complement each other.
One possible reason could be that Lucy is too focused on her own goals, like becoming a stronger mage or achieving something specific in the guild. She might see a romantic relationship as a distraction at that moment.
A possible plot could be that their married life is disrupted by a mysterious force that is causing chaos in the magical world. Natsu and Lucy, being the strong couple they are, set out to find the source of this problem. As they journey, they discover secrets about their own powers and how their union might be the key to saving the world. There could be moments of doubt and fear, but their love for each other always pulls them through.
One possible plot could be that Natsu and Lucy go on a dangerous mission together. In the middle of it, they find a mysterious lemon - like magical item. As they study it, they start to feel a strange warmth between them. They then have to overcome their initial shyness and admit their feelings for each other while dealing with the power of this strange item.
A possible storyline is a friendly competition between them. They bet on who can complete a series of challenges first. These challenges could involve things like rescuing a certain number of people in a village within a time limit, or collecting rare magical items. Along the way, they learn more about each other's strengths and weaknesses, and also grow closer as friends. This kind of storyline can also have some humorous moments, like when Natsu accidentally sets something on fire during a task that Gray then has to quickly freeze to prevent a disaster.
The 'lemon' aspect, which often implies some level of romantic or spicy content, adds an extra layer of intrigue. Fans enjoy seeing different interpretations of the relationships between these characters, whether it's a Gray - Lucy pairing, a Natsu - Lucy pairing, or some complex love triangle situation. It allows for a lot of creativity in the fanfiction writing, as authors can play with the characters' emotions and interactions in ways that the original series might not have fully explored.
You can try fanfiction.net. It has a large collection of fanfictions from various fandoms including ones related to Natsu, Gray and Lucy.