There are often fanfictions where Sans acts as a sort of protector for the depressed reader. He senses their pain and stands by them, like a silent guardian. He might not always have the right words, but his presence is comforting. In some stories, he'll even take the reader on little adventures through the Underground to show them there's more to life than their current state of mind.
A common theme is hope. Sans often represents a glimmer of hope for the reader. He shows that there are people (or in this case, a skeleton) who care and can help them through tough times.
One common theme is redemption. The reader often tries to redeem Sans from his depressive state, giving him a new lease on life. For example, in many fics, the reader's kindness and understanding slowly pull Sans out of his darkness.
There's also 'Finding Sans' which is a great 'depressed sans x reader fanfic'. In this one, the reader stumbles upon a very different side of Sans. It delves deep into his emotions and how the reader gradually gets closer to him. It has some really touching moments as the reader tries to understand and help Sans deal with his depression.
One great fanfiction could be 'The Dark Days of Hermione'. It really delves into her internal struggles and how she copes with her depression. It shows her trying to hide it from her friends at first and then gradually opening up.
There's also 'Peter Parker: Lost in the Shadows'. This fanfic shows how his depression can isolate him from his friends and family. It has some really poignant moments where you can feel his pain through the words. It's a bit darker than the regular Spider - Man stories but it gives a unique perspective on his character.
One great 'depressed reader fanfiction' could be those that focus on the journey of self - discovery and healing. For example, stories where the reader character finds support in unexpected friendships within the fanfiction's universe. Another good one might be the ones that deal with the reader's internal struggles in a very relatable way, like how they cope with daily stressors and gradually find their own strength.
Another interesting one is 'When Percy Lost His Spark'. Here, the author explores Percy's depression as a result of the constant pressure he's under to save the world. It's a unique take as it not only shows his emotional turmoil but also how it affects his relationships with his family and remaining friends.
You can start by looking on popular fanfiction websites such as Archive of Our Own (AO3). It has a large collection of Undertale fanfictions, including those featuring Fresh Sans. Another option is FanFiction.net, which also has a wide range of works.
One common theme could be the struggle with inner demons. Since Nightmare Sans is often depicted as a rather complex and troubled character in the fanfiction. Another theme might be the search for redemption or a way out of his depressed state. It could also explore themes of isolation, as his depression may lead him to push others away.
Well, 'Sans and the Reader: A New Beginning' is quite good. It starts with the reader arriving in the Underground and gradually developing a deep bond with Sans. The story does a great job of exploring Sans' character while also showing the growth of the relationship. There's also 'The Sans x Reader Encounter' which is known for its unique writing style that makes the interactions between the two feel very real.