In 1965, Jellal Uri directed a film about a complicated love story. The film was praised as a classic in the history of film because of its outstanding performance in the plot and character creation.
One possible plot could be that Naruto somehow gets transported to the world where Jellal is. He has to adapt to the new magic - based environment using his ninja skills. Maybe he is mistaken for Jellal at first and has to deal with the consequences of that identity mix - up.
One common theme is their shared history. Given their past interactions in the original story, many fanfics explore how they come to terms with what happened between them before. Another theme is friendship. Even if they have a complex relationship, the idea of them being friends and having each other's backs is popular.
Yes, there are quite a few. You can start by looking on popular fanfiction websites like Archive of Our Own. Just search for 'Jellal and Lucy' and you'll find a variety of stories ranging from sweet romances to more action - packed adventures with a romantic subplot.
One common theme could be the reaction of their friends and the surrounding community to the pregnancy. Another might be how Jellal and Lucy themselves adjust to the new situation.
I'm not sure specifically which 'Jellal and Lucy pregnant fanfiction' is good. You could try searching on popular fanfiction websites like FanFiction.net or Archive of Our Own. Maybe look for ones with high ratings and positive reviews from other readers.
Love and redemption are common themes. Given their past, Jellal has a lot to atone for, and in many fanfics, Erza's love becomes a part of his redemption journey. Another theme is the struggle between duty and personal feelings. They both have important roles in their world, and finding a balance between that and their relationship is often explored.