One common theme is the healing of emotional wounds. Hanzo has a lot of past traumas, and Mercy, with her kind and nurturing nature, can be depicted as helping him overcome those. For example, she might help him come to terms with his actions in the Shimada clan.
You can try some popular fanfiction websites like Archive of Our Own (AO3). It has a large collection of Overwatch fanfictions, including those about Hanzo and Mercy. Just search for 'hanzo x mercy' in the search bar, and you'll get a list of relevant stories.
One aspect of Hanzo x Widowmaker fanfiction could be the exploration of their contrasting personalities. Hanzo is often portrayed as a brooding and honor - bound character, while Widowmaker is cold and efficient. In fanfictions, their relationship might start from an unexpected encounter on the battlefield. For example, they could be forced to team up against a common enemy, which then leads to a growing understanding and attraction between them.
A common theme is the redemption arc. Since Widowmaker has a rather dark past as a brainwashed assassin, in some fanfictions, Hanzo could be the one to help her break free from the control of Talon and find her true self again.
Friendship - turned - love is also quite common. They begin as comrades or reluctant allies and as they spend more time together, their relationship deepens into something more romantic. This progression is seen in a lot of 'hanzo x mcree fanfiction' as it adds an interesting dynamic to their characters.
One popular theme is redemption. Hanzo might try to help Widowmaker break free from her programming or past traumas. Another theme is the enemies - to - lovers trope, as they are on different sides in the Overwatch universe. They could start off as adversaries but gradually develop feelings for each other.
You can start by looking on Archive of Our Own (AO3). It has a vast collection of fanfiction for all kinds of pairings, including mccree x hanzo. The site has a great search function that allows you to filter by tags, ratings, and word count.
One common theme is the clash of their cultures. Hanzo is from a very different cultural background compared to Sonya. Their different values and ways of life often create interesting dynamics in the stories.
One great mccree x hanzo fanfiction could be 'The Meeting on the Bridge'. It beautifully depicts their first encounter and the initial sparks of an unexpected friendship. The story focuses on how their different personalities, McCree's laid - back cowboy nature and Hanzo's more reserved samurai - like demeanor, start to complement each other.
Yes, there are quite a few. You can start by looking on popular fanfiction websites like Archive of Our Own. Just search for 'Hanzo Hasashi x Sonya' and you'll find a variety of stories, ranging from action - packed adventures where they team up against common enemies, to more character - exploration - based stories that delve into their complex relationship.