His friend Ron could come back to help him. Ron is always loyal and might not want to leave Harry behind. He could bring his family's flying car again to pick up Harry.
Maybe he has to find an alternative way to get to school. He could try to use magic to create a makeshift transportation or ask for help from his friends' families who might be passing by.
I'm not sure if there is such a fanfic. Fanfics cover a wide range of themes and scenarios, but this particular one might be quite rare or even violate some of the general guidelines of the Harry Potter fanfic community. Many fanfic platforms have rules against inappropriate or non - canon - compliant content.
There probably is. Fanfic communities are full of unique and unexpected plot ideas. This kind of plot would completely turn the original story on its head. It might involve some sort of alternate reality where Harry and Voldemort have a common goal or where they are forced to work together due to some external threat. It could be a really interesting read for those who like exploring different interpretations of the Harry Potter universe.
At first, it would be extremely tense and full of suspicion. Harry would be very wary of Voldemort's motives for protecting him. Voldemort, on the other hand, might be impatient with Harry's lack of trust.
Perhaps Voldemort discovers that there is a greater threat out there. In the fanfic, it could be that another dark force is emerging, and Voldemort sees Harry as an ally of sorts against this new threat. So, he decides to protect Harry in order to deal with this common enemy.
Snape could also be a character in such a fanfic. His complex relationship with both Harry and Voldemort makes him an interesting addition. He might be in a difficult position, having to keep his cover as a double - agent while also trying to find a way to save Harry without revealing his true intentions to Voldemort.
At first, it would probably be very tense. Harry would be suspicious of Voldemort's motives, and Voldemort would be cautious of Harry's potential to rebel. But as time goes on, they might develop a strange sort of understanding. Harry could start to see Voldemort as more than just a pure evil figure, and Voldemort might start to view Harry as something more than an enemy.
Ron would also be important. His loyalty to Harry is unwavering. He might be the one who bravely volunteers to go on the most dangerous part of the rescue mission, perhaps facing off against some of Voldemort's most feared Death Eaters.
Hermione could be a main character. She might be trying to find a way to rescue Harry from the timeout situation. Ron could also be there, supporting Hermione in her efforts.