Friendship development is a common theme. Writers often explore how Neal and Phil's relationship grows from acquaintances to close friends or something more.
You could also check out fanfiction.net. Sometimes, if you search specifically for 'neal x phil', you might find some interesting stories. However, the quality can vary, so it's good to read the summaries and reviews first.
The theme of loyalty is also quite prevalent. In these fanfictions, phil and steve are shown to be loyal to each other no matter what difficulties they face. This loyalty can be tested in various ways, such as by outside forces trying to break their bond or by internal conflicts within themselves regarding their relationship.
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.
One common theme could be the exploration of complex emotions between the two characters. Since it's 'frustrated', perhaps unrequited feelings or misunderstandings play a big part.
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.
Friendship is another theme. Some fanfictions focus on building a strong friendship between Link and the reader. They might go through challenges together and grow closer as friends, sharing inside jokes and having great conversations.
In some fanfictions, they may also interact with other secondary characters. For instance, they could be working with a group of mentees or colleagues. These secondary characters could add more depth to the story and serve as a contrast or support to the main characters, Dr Phil and Steve Harvey.
Another option is to check out specific fandom - related websites. Sometimes, smaller, more niche websites dedicated to the fandom that phil and steve belong to might have some unique and interesting phil x steve fanfiction. These can offer a different perspective compared to the larger, more general fanfiction platforms.