I really like 'Sanegiyuu: The Unspoken Understanding'. It delves deep into the unspoken connection between Sanemi and Giyuu. The author does an amazing job of portraying their internal struggles and how they gradually come to understand each other better. There are some really touching moments in this fanfic that make it a must - read for sanegiyuu fans.
Social media platforms like Tumblr can also be a good source. There are many fans who post about their favorite sanegiyuu fanfics on there. You can search for relevant tags such as #sanegiyuu #fanfic and explore the posts to find some good reads.
In a Giyuu x Shinobu fanfic, the setting and plot can vary widely. Some might be set during the main events of the Demon Slayer universe, with them facing demons together. Others could be more of an alternate universe story, where they meet under different circumstances, like in a modern - day high school AU. The fanfic could also delve into their backstories and how those experiences shape their relationship. For instance, Shinobu's past with her sister could play a role in how she opens up to Giyuu, and vice versa for Giyuu's own traumas.
I would recommend 'Whispers of the Heart' for Giyuu x Shinobu fans. This fanfic focuses on their unspoken understanding. It's full of small moments that build up their relationship, like when Shinobu leaves a small flower on Giyuu's doorstep as a sign of her care. Also, 'Shadows and Sunlight' is worth checking out. It has a great plot that involves them having to go on a secret mission together and how that journey changes their relationship from colleagues to something more intimate.
Angst fiction, well, it's basically about exploring the darker and more troubled aspects of human emotions through fictional stories. For example, a story might be about a young person struggling with self - identity in a cruel society. They face a lot of angst because they don't fit in and are constantly at odds with themselves and the world around them. It can be a very powerful form of storytelling as it delves deep into the human psyche.