Ruby would be deeply saddened. She might blame herself for not being able to protect Blake. Weiss would probably be in shock at first, then become more determined to fight against whatever caused Blake's death. Yang would be furious and seek revenge. She has a very close bond with Blake, and her death would likely fuel Yang's anger towards the enemy.
The other characters would have a range of reactions. Pyrrha, if she were still alive in the fanfic's context, would be heartbroken. She would see Blake as a fellow fighter and her death would be a great loss to the cause. Ren and Nora would also be affected. Ren might become more withdrawn, while Nora would be more vocal about their loss and would want to take immediate action. Ozpin would likely view it as a significant setback in the fight against evil and would try to use it as a motivation for the remaining characters to be stronger.
The other members of Team RWBY would be deeply affected. They would start to question their own abilities and the purpose of their fight. Some might withdraw into themselves, like a broken Weiss who shuts out the world for a while. Yang, on the other hand, could become reckless in her pursuit of vengeance, endangering herself and others. Blake would try to hold the team together, but she would also be mourning privately. The other friends and allies in the RWBY universe would also be in mourning. Qrow might blame himself for not being there to protect Ruby, and Ozpin would see it as a great setback in the fight against evil.
In some scenarios, she might die heroically in a battle against a powerful Grimm. For example, she could sacrifice herself to save her friends from a horde of Nevermores. Another possibility is that she succumbs to an unexpected betrayal within the story, perhaps by a character who was thought to be an ally. Or she could die due to some unforeseen magical or technological accident in the RWBY universe.
Ruby would be devastated. Qrow is her uncle and has been an important figure in her life. She might initially go into denial and then be filled with rage, vowing to avenge his death. She could become more determined than ever to take down Salem, seeing it as the only way to make his sacrifice meaningful.
Hermione would likely be devastated. She might go into a deep state of mourning, but also use her intelligence to try and figure out what led to Harry's death. Ron would be angry and heartbroken at the same time. He'd probably want to seek revenge if there was someone or something responsible.
Uraraka would be heartbroken. She was one of Deku's closest friends. She might lose some of her usual cheerfulness and become more focused on finding out who or what was responsible for his death. She could also struggle with her own self - confidence in using her quirk, as Deku was always an inspiration to her.
Yes, there might be some out there. You can check fanfic platforms like Archive of Our Own. However, keep in mind that the quality can vary greatly. Some might focus on the emotional impact of Blake's death on other characters, while others could be more action - oriented in the lead - up to her death.
In RWBY fanfics that deal with Blake's depression, it often explores her past traumas. Her experiences with the White Fang and the discrimination she has faced can be deeply ingrained. Writers may show her withdrawing from her friends, like how she sometimes isolates herself in the series. This can be a way to delve deeper into her character, beyond what the show has already presented.
Isolation and belonging are also common. Blake has had moments of feeling alone, and fanfics play with this idea. They might show her finding a new sense of belonging or struggling with her place in the world. It's a theme that really ties into her character arc in the original show.
Ron and Hermione would be completely shattered. Ron, who had been Harry's friend since the beginning, would probably be in denial at first. Hermione would likely try to figure out what exactly happened. Dumbledore would be solemn and would try to keep the school calm while also investigating the matter. Hagrid would be inconsolable, crying his eyes out. The other students would be in a state of shock and sadness. The teachers would also be deeply affected, especially those who had taught Harry or had some connection with him.
Sakura would be devastated. She has always seen Naruto as a dear friend and teammate. She would probably blame herself for not being strong enough to prevent his death. Sasuke, on the other hand, might feel a deep sense of loss and anger. He might go on a solitary journey to find out who was responsible.