Yes, there might be some out there. You can start by looking on fanfic websites like Archive of Our Own. They usually have a wide range of fanfictions including yaoi ones. Just search for 'jack frost x jamie' in their search bar and you'll likely find several stories.
One common theme could be the exploration of their relationship in a new and different setting than the original source. Maybe they are in a modern AU (alternate universe) where they have to deal with normal life problems while also being in a relationship.
One example could be a story where Jack Frost and Jamie share a magical adventure together. In this fic, their relationship might start as a friendship that gradually develops into something deeper. They could face challenges like a powerful winter spirit trying to disrupt the peace, and through their bond, they overcome it.
Definitely. A lot of fanfiction writers are attracted to this pairing. You can often find works that are well - written and full of creativity. These stories might take the basic idea of their connection from the original source and expand it in all kinds of imaginative ways. For example, they could create scenarios where Jack Frost has to protect Jamie from some new threat in a magical realm, or they could explore how Jamie's growing up affects their relationship.
One common theme is friendship. Their bond as a human and a magical being is often explored. Another is growth, like Jamie's growth in understanding the magical world because of Jack. Also, adventure, as they might go on various adventures together in the stories.
Belonging is another important theme. Jack, who is often seen as an outcast in the spirit world, finds a sense of belonging with Jamie. And for Jamie, he feels like he belongs to a more magical and special world when he is with Jack. This mutual feeling of belonging strengthens their relationship and is a key aspect in many of the fanfictions about them.
Fanfiction.net might also be a place to search. But it has a different tagging system compared to AO3. You may need to do a more general search for 'Jack Frost' and 'Jamie' and then skim through the results to find ones that involve the mpreg concept. Keep in mind that the quality and content can vary widely on this site.
I'm not sure specifically about 'jack frost x bunnymund yaoi fanfiction'. You could try searching on some well - known fanfiction websites like Archive of Our Own. There might be some works there.
One common theme could be the exploration of their different personalities. Jack Frost is often seen as more carefree and mischievous, while Bunnymund is more grounded. Their relationship in the fanfiction might play on how they balance each other out.