The antagonists could be dark guild members. They might hear about the special baby that Lucy and Laxus are involved with. Maybe the baby has some sort of powerful magic within it, and the dark guild wants to steal the baby for their own evil purposes. So they constantly try to attack Lucy and Laxus to get their hands on the baby.
For Laxus, he might become more gentle and patient. Usually seen as a tough and somewhat brash character, having a baby could soften him. He would learn to control his temper better around the baby. For Lucy, she would likely become more confident in her maternal abilities. She has always been kind - hearted, but now she has to be strong for the baby. She might also develop new magical skills or ways to protect the baby.
One common theme could be family building. Since there's a 'baby' involved, it often explores how Laxus and Lucy adapt to becoming parents and building a family together. Another theme might be the growth of their relationship. Having a baby can put a strain or strengthen their bond, and this is often explored in such fanfiction.
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 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.
I'm not sure of specific 'laxus x lucy baby fanfiction' stories off the top of my head. But you could try searching on fanfiction websites like Archive of Our Own or FanFiction.net. They usually have a wide variety of fan - created stories in different categories, and you might be able to find some interesting ones related to this pairing there.
Some people also recommend following specific Fairy Tail fanfic writers on social media platforms. They might announce when they've written a new Lucy x Laxus piece or share links to their works. Additionally, if you're part of a Fairy Tail fan club or group, asking around there could lead you to some great fanfictions.
One common theme is friendship. They often start as acquaintances or even rivals and gradually become friends. Another theme is adventure. They go on various quests and battles together in many fanfictions.
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.
There could also be other supporting characters from the Fairy Tail guild. For instance, Mirajane might play a role in giving advice to Lucy about pregnancy and motherhood, since she has a nurturing side. And Makarov, as the guild master, could be involved in ensuring the safety of Lucy and the future of the guild with a new member on the way.