I really like 'Partners in Science'. In this fanfiction, Peter and Bruce start working together after Peter discovers some strange radiation that he can't figure out on his own. Bruce helps him analyze it, and their friendship grows throughout the story. It has some really cool action scenes where they have to fight off bad guys who are also interested in the radiation.
Often, she is depicted as being just as intelligent as the male Bruce Wayne. For example, she has a sharp mind for detective work and strategy. She might be able to quickly analyze crime scenes and figure out the motives of the villains.
Another theme is the exploration of their dual identities. Peter has to balance his life as a student and Spider - Man, and Bruce has his own struggles with the Hulk. Fanfictions often explore how they can relate to each other's problems and support one another in dealing with their identities.
Perhaps they would team up to fight a common enemy. Peter's agility and combat skills combined with Bruce's Hulk - like strength could make for a formidable duo. They could be facing a villain who is both a scientific threat and a physical menace.
One common theme is mentorship. Bruce could be a mentor to Peter, guiding him with his scientific knowledge. For example, in some fics, Bruce helps Peter with his web - shooter technology.
He might develop a greater sense of humility. Without the Batman persona to fall back on, he has to face his own limitations as a person. For example, he may struggle to get people to listen to his ideas for change when he doesn't have the intimidation factor of Batman.
One great fanfic is 'The Father - Son Bond'. It beautifully explores the complex relationship between Bruce and Damian. It shows how Bruce tries to be a good father while also dealing with his role as Batman, and Damian's struggle to fit into this new world with his own strong - willed nature.
One possible plot could be them trying to balance their superhero lives with their married life. They might face challenges like keeping their identities secret from each other at first, and then the drama unfolds when they finally discover the truth. It could also involve them teaming up to fight a common enemy while also dealing with the typical married couple issues like misunderstandings and family planning in the superhero world.
You can try fanfiction websites like Archive of Our Own (AO3) or FanFiction.net. They have a vast collection of fanfictions on various topics, including the pairing of Peter Parker and Helena Wayne. Just use the search function on these sites and type in the relevant keywords.