One plot idea could be that Lucy and Laxus accidentally travel back to a time when Fairy Tail was first founded. They could meet the younger versions of the guild members and get involved in the early struggles of the guild. For example, they might help in a battle against a rival guild that was trying to stop Fairy Tail from being established.
Another plot could be that they travel to a future time where Fairy Tail has been destroyed. They then have to figure out what led to this destruction and try to change the future. Maybe they discover that a dark magic user had risen to power and they need to find a way to stop this person in the past to prevent the future disaster.
One idea could be that they discover the pregnancy unexpectedly. Maybe they were in the middle of a big adventure in their magical world and then Lucy starts showing signs. It throws them into a new set of challenges as they have to balance their duties in their guild with preparing for a new life.
Well, she could time travel to a prehistoric age. Imagine Lucy having to survive among dinosaurs and primitive humans. She might accidentally change the course of evolution in some small way. Or, she could travel to different historical battles, like the Battle of Waterloo. There, she could use her knowledge of the outcome to either save lives or cause some unforeseen chaos. It all depends on how you want to write the story.
Well, a possible plot is that there are some dark forces that target Lucy because of her unborn child. Maybe they believe the baby will have some special powers. Laxus then has to go on a journey to find a way to protect them. And as for their relationship, it could be strained at first because of the stress, but they gradually grow closer as they face the challenges together. Plus, there could be a sub - plot about how Lucy's celestial spirits react to the news. Some might be overjoyed and offer their own unique forms of protection.
If they travel to a future where things are very different, they might see new sides of each other. Laxus might see Lucy in a more confident and powerful role in the future, which could make him respect her even more. And Lucy might see Laxus in a more mellow or perhaps more burdened state, which could make her more empathetic towards him. This could lead to a deeper emotional connection between them.
Well, perhaps Laxus has some misguided notion that Lucy has information vital to the guild's safety. So he kidnaps her thinking he can extract it from her quickly. But in reality, Lucy has no such information and she has to convince Laxus of that.
One possible plot development could be that Laxus initially struggles with the news. He might be worried about his ability to be a good father. However, as time passes, he realizes his love for Lucy and their unborn child and starts to prepare for the new addition to their lives. For example, he could start training harder to be a protector of his family.
One possible plot could be that Lucy and Laxus accidentally end up having to take care of a baby together. Maybe they find a lost baby during one of their guild missions. At first, they're both really clumsy and unsure of how to handle it. But as time goes on, they start to develop a bond not only with the baby but also with each other in a new, more family - like way.
One great Laxus and Lucy fanfiction is 'A Bond Beyond Guilds'. It focuses on how they team up for a difficult mission and gradually discover a deep connection. Another is 'Laxus and Lucy: The Unexpected Alliance' which shows how their different powers complement each other in unexpected ways. And 'Lucy's Encounter with Laxus' is also interesting as it delves into their first meeting from Lucy's perspective.
One possible plot could be that they accidentally end up having to take care of a baby during a mission. Maybe they find an orphaned baby in a dangerous situation and decide to protect it. This could lead to some really cute and funny moments as they struggle to take care of the baby's needs while also dealing with the threats around them.
Well, a great plot could involve them facing some challenges during the pregnancy. For instance, Mirajane might have some difficulties with her magic due to the pregnancy hormones. And Laxus would be super protective, which could lead to some interesting conflicts within the guild when he overreacts to perceived threats. Also, they could discover some old family traditions related to pregnancy and childbirth that they decide to incorporate.