It would be a very strange and unorthodox take on the characters. Aragorn is typically seen as a noble and just leader, and Boromir is a proud warrior. This scenario would completely change the dynamic between them and might be seen as a form of discipline in a rather odd context within the story.
I'm not sure if there is such a specific fanfic. Fanfics cover a wide range of themes and scenarios, but this particular one seems rather unorthodox. It might exist in some corner of the vast fanfic universe, but it's not a common or widely known concept.
He could meet Frodo. Frodo is a very important hobbit, and Aragorn might have an interesting conversation with him about the Ring and their different experiences.
You can start by looking on fanfiction.net. It has a large collection of fanfics from various fandoms, including many about Boromir.
One great 'boromir x reader fanfic' is 'The Unseen Bond'. It beautifully captures the essence of Boromir's character and his relationship with the reader. The story is filled with adventure and emotional depth.
One common theme is redemption. Since Boromir's character in the original story had some flaws and made mistakes, in these fanfics where he lives, he often gets the chance to redeem himself. For example, he might make amends for his actions regarding the One Ring.
Aragorn may develop a more complex relationship with power. As the Ringbearer, he has to constantly battle the allure of the Ring's power. This could lead to him becoming more humble as he realizes how easily power can corrupt, even someone as strong - willed as him. He might also grow in his understanding of the smaller races, like the hobbits, who he now has a new - found respect for since he is in a position similar to Frodo's.
I really like 'Aragorn and Eowyn: Paths Not Taken'. This fanfic takes a different turn on their story. It imagines a scenario where Aragorn and Eowyn have more time to get to know each other on a personal level. It's beautifully written, with great descriptions of their emotions and the world around them.
One great fanfic is 'The Bond Beyond Rivendell'. It beautifully depicts Aragorn and Legolas' friendship as they face numerous challenges in Middle - earth together. Their unwavering loyalty to each other is shown through various battles and adventures. It also delves into their personal conversations, revealing a deep understanding and respect between them.
A common theme is Aragorn's leadership. Many fanfics explore how he leads Gondor and the other kingdoms, like in 'The Leadership of Aragorn' where it shows his decision - making process. Another theme is his relationship with Arwen, as seen in 'Aragorn and Arwen: Love in Middle - earth'. And his ranger past often comes up, like in 'Aragorn: Return to the Ranger's Life' which focuses on his skills as a ranger.
A good 'boromir x reader fanfic' should have a strong understanding of Boromir's character. His noble yet flawed nature needs to be accurately portrayed. For example, his pride and his loyalty to Gondor are important aspects.