There are often fanfiction pieces that explore the relationship between Bilbo and the reader in a romantic way. For example, a story could start with the reader being a new arrival in the Shire and gradually falling in love with Bilbo as they get to know his kind and curious nature. You can search for these by using specific tags like 'Bilbo Baggins x Reader' and 'Romance' on fanfiction websites.
One common trope is the 'fish out of water' scenario. The reader, coming from a different world or background, has to adjust to the Shire's ways. For example, they might be confused by the hobbit's love for simple pleasures like gardening and smoking pipe - weed. Another trope is the 'damsel/gentleman in distress' where either Bilbo or the reader gets into trouble and the other has to save them during an adventure.
There are many out there. Some explore Bilbo's pain during his time in the Lonely Mountain, like 'Bilbo's Trials at Erebor'. It shows how the dragon's presence and the battles affected him deeply. These fanfictions often take the original character traits of Bilbo and expand on the idea of his hurt in different situations.
There is a fanfiction called 'Bilbo the Blood - Drinker'. In this story, Bilbo becomes a vampire during his adventures. It explores how his relationships change, especially with the dwarves. They are initially afraid but then come to accept him as he uses his vampire powers to their advantage during their quests.
A very popular one is 'Bilbo's Unforeseen Ally'. The OC in this story is an elf - maiden who has been exiled from her own realm. She teams up with Bilbo and they face many challenges together. The author does a great job of showing how Bilbo's hobbit - sensibilities and the elf - maiden's grace and skill complement each other in their adventures.
There's also a fanfic called 'Bilbo's Youthful Escapades'. In this story, it focuses on Bilbo's friendships during his younger years and how they shaped the hobbit he would become later. It's full of heartwarming moments and a bit of adventure as well. It really delves into the idea of what made Bilbo so curious and brave from a young age.
I've also heard of 'Bilboa: The Female Hobbit'. This fanfiction not only changes Bilbo's gender but also delves deeper into the hobbit culture from a female perspective. It explores how a female Bilbo might interact with the male - dominated hobbit society, all while going through the main events of the original story with a fresh take.
I'm not sure of a specific 'angry bilbo baggins fanfic' off the top of my head. But you can try looking on fanfic websites like Archive of Our Own. There might be some stories there that explore an angry Bilbo Baggins in various scenarios, such as during his adventures when he's faced with difficult challenges or when he has disputes with other characters in Middle - earth.
I'm not sure of a specific 'bilbo baggins cat familiar fanfic' off the top of my head. But you could try searching on fanfiction platforms like Archive of Our Own. There might be some creative stories there that combine Bilbo Baggins and a cat familiar in interesting ways.
One great 'bamf Bilbo Baggins fanfic' is 'The Adventures of BAMF Bilbo'. It really shows Bilbo in a new light, with him being much more assertive and powerful than in the original story. Another one could be 'Bilbo's Hidden Strength' which delves into how Bilbo could have been a real force to be reckoned with in different situations.
One great 'female Bilbo Baggins fanfic' could be 'The Adventures of Female Bilbo'. It often portrays her in a new light, taking on quests with a different perspective. Another is 'Bilboa: The Female Version' which might show how she could have changed the dynamics of the original story.