One of the very common themes in izumi curtis crossover fanfiction is the exploration of power dynamics. When she crosses over into another universe, her alchemical abilities might be perceived differently. In some crossovers, she could be seen as a powerful figure, while in others, she might be relatively weak compared to the new world's powerhouses. This exploration of how she navigates in these different power hierarchies is often a central theme. Additionally, themes of family and loyalty can also be explored in new and interesting ways when she is in a crossover situation, as she may encounter new family - like bonds or have to reevaluate her loyalty to her original world and relationships.
One great source for izumi curtis crossover fanfiction could be Archive of Our Own (AO3). There are many talented writers who create interesting crossovers there. Just search for 'izumi curtis crossover' on the site and you'll find a variety of stories.
Sure, there are probably some great Olivier Mira Armstrong x Izumi Curtis fanfictions. A lot of fanfiction writers are creative and come up with unique scenarios for different character pairings. To find them, you could also join relevant fan communities on social media platforms. Members there might be able to recommend some really good fanfictions that feature this particular pairing. They might even share their own works if they have written any for this pairing.
One common theme could be friendship. Given their different personalities, exploring how they become friends or support each other can be interesting. Another might be adventure, as they both are strong - willed characters who could embark on various adventures together.
Curtis Clark in the 'Curtis Clark Ghost Story' is likely the person who either experienced the ghostly events or is the one who first told the story. He could be an ordinary person who had an extraordinary encounter with the supernatural.
In many 'Batman Beyond' fanfictions where Dana finds out, it could be about her finding out Bruce Wayne is Batman. Maybe she stumbles upon some evidence in the Batcave or notices some similarities in Terry's behavior to Bruce. For example, she might notice Terry's fighting style is similar to what she's heard about Batman's. It could also be that she discovers some secret technology related to Batman that leads her to the truth.
Ginny's reaction could also involve a sense of helplessness at first. But then she'd quickly gather herself and use her resources. For instance, she might call on her friends and family for help. She'd be by Harry's side constantly, using her presence to comfort him and also using her knowledge of magic to try and ease his pain.