One great 'neal x peter fanfiction' story is 'The Unlikely Bond'. It focuses on how their relationship evolves from distrust to a deep friendship. The author does an amazing job of showing Neal's charm and Peter's steadfast nature.
You can try Archive of Our Own (AO3). It has a large collection of fanfiction, including many 'neal x peter' ones. The site has a good search function that allows you to filter by tags like 'neal x peter' and other relevant criteria.
Mystery - solving is also a common theme. Given that they are often involved in cases in the original show, fanfiction might continue this trend. They could be on the hunt for a priceless artifact or trying to track down a master criminal. Their combined skills - Neal's knowledge of the criminal underworld and Peter's FBI resources - make for exciting mystery - solving adventures.
The settings in neal and peter slash fanfiction can vary widely. Some might be set in the canon - like settings of the show they are from, while others might take them into alternate universes. This allows for different interpretations of their relationship. For instance, an AU where they meet in a completely different situation, like in a college campus, and their relationship develops from there.
Popular 'neal and peter fanfiction' often focuses on their unique relationship. It shows the trust that builds between them despite their differences. For example, many fictions explore how Neal, with his criminal past, and Peter, the law - enforcer, come to rely on each other.
Fanfiction.net might also have some Peter Briggs x Neal Caffrey fanfiction. You can search by the characters' names and sort through the results. Some stories could be about their friendship evolving over time. Maybe it starts as a professional relationship where Peter is constantly trying to keep Neal in line, but then they gradually become closer friends and rely on each other more than they expected.
Neal might interact with Peter's son in a friendly and mentoring way. He could share his knowledge of art and culture, given his refined tastes. Maybe he'd teach the son some tricks about reading people, which is one of Neal's skills.
One common theme is the relationship between Neal and Peter. It could be about their friendship evolving into something deeper, like a father - son or a mentor - mentee relationship with a lot of emotional depth. Another theme is their adventures outside of the main plot of the show. For example, they might go on a secret mission together that wasn't in the original series.
The theme of vulnerability is also prominent. Neal being hurt makes him vulnerable, and Peter's concern is a way to protect that vulnerability. It can also explore themes of trust, as Neal has to trust Peter to take care of him when he's in a weakened state. Additionally, there might be themes of redemption, where Neal's injury makes him re - evaluate his actions and Peter is there to support his growth.
In such fanfictions, their relationship is often depicted as very deep and complex. Peter is like a guardian to Neal. For example, when Neal is in danger, Peter will use all his resources to protect him. It's like a father - son or an older - brother - younger - brother kind of relationship.