A really interesting fanfic is 'Lupin and Snape: A Forced Bond'. In this one, Dumbledore forces them to collaborate on a top - secret project. As they work side by side, they gradually understand each other more. It's full of great dialogue that really captures the essence of their characters.
Mpreg (male pregnancy) fanfiction involving Severus Snape and Remus Lupin often explores unique and creative storylines. Some might focus on how the magical world in the Harry Potter universe would react to such an extraordinary event. It could also delve into the relationship dynamics between Snape and Lupin, which were complex in the original series, and how having a child together would change or deepen their connection.
A time travel story could also explore how Remus Lupin and Severus Snape's relationship evolves in a different timeline. Perhaps they travel to a time when they were supposed to be friends but something went wrong in the original timeline. They might discover new aspects of each other and form an unlikely alliance that could change the future of the wizarding world.
Another theme is the adaptation to the new situation. They have to deal with the physical and emotional changes that come with the male pregnancy. For example, Lupin, being a werewolf, might have additional concerns about how his condition could affect the pregnancy, and Snape would use his potions knowledge to try and ease any difficulties.
The complex relationship between them. In the original books, they have a history of animosity and mistrust. Fanfiction allows writers to explore how they could overcome this, or at least understand each other better. It's like filling in the gaps that J.K. Rowling left.
The plot could be that a magical artifact sends them back in time. Lupin and Snape find themselves in the middle of a major event in Hogwarts' history, like the founding of the Marauders. They have to navigate through this new situation while also dealing with their own personal issues. Snape may be trying to use this time to change some things related to Lily Potter, and Lupin might be more focused on the fate of his friends.
One common theme is redemption. Since both characters have had their share of dark moments or are misjudged, fanfictions often explore their journey towards redemption. For example, Snape's actions towards the end of the original series are often further explored in terms of his true motives and how he might be redeemed in the eyes of others, especially Remus.
One great Lupin and Tonks fanfiction is 'The Lupin - Tonks Story' on FanFiction.net. It really delves into their relationship, from their initial meetings to the deeper emotional bonds. The writer captures Tonks' free - spirited nature and Lupin's more reserved personality very well, making their interactions seem natural.
I really liked 'Lupin and Black: Unspoken Bonds'. In this fanfic, the relationship between Remus and Sirius is explored in a post - Hogwarts setting. It's a story full of mystery and adventure as they work together to solve a dark magic mystery that's plaguing the wizarding world. Their bond is shown to be unbreakable, even in the face of great danger.
I really like 'Remus Lupin's Unlikely Mate'. It's a story that takes an unexpected turn in terms of who his mate is. It has a lot of adventure in it. Remus and his mate go through various challenges together, which makes their relationship more believable and engaging.
There's also 'Snape's Hidden Past with James Potter'. This fanfiction explores Snape's side of the story more. It reveals some secrets about his early interactions with James that were not shown in the original books. It gives a more sympathetic view of Snape and shows how James, in some ways, misjudged him all those years ago.