Well, I really liked 'The Time - Albus Severus Adventure'. It has Albus Severus accidentally traveling to a time when Hogwarts was just being built. He has to figure out how to get back while also learning a lot about the origins of magic in Hogwarts. It's a really cool concept and the author does a great job of describing the ancient Hogwarts. There are also some really neat time - travel paradoxes explored in it.
In some Albus Severus time travel fanfiction, the plot involves him going back to the time of the founders of Hogwarts. This is fascinating because he gets to interact with the likes of Godric Gryffindor and Salazar Slytherin. He might have to choose sides in an old conflict or even try to prevent the split between the houses. It's a really cool concept that explores the roots of Hogwarts and the wizarding world. Also, there are plots where he travels to a time when dark magic was on the rise and he has to fight against it using his knowledge from the future.
One idea could be Albus Severus Potter traveling back in time to meet his father, Harry Potter, as a young student at Hogwarts. He could then help his father in some of the early battles against Voldemort, using the knowledge he has from the future. This would create a lot of interesting interactions and changes to the original story line.
One possible antagonist could be a dark wizard from the past who somehow catches wind of Albus Severus' time - traveling and decides to use his knowledge of the future for his own evil purposes. Maybe a forgotten Death Eater who was thought to be dead but actually survived in hiding and now sees this as an opportunity to rise again.
Most likely, his parents, Harry and Ginny Potter, could send the howler. They would be concerned about their son's well - being and actions at Hogwarts. If Albus got into trouble or was not living up to the Potter family name, they would not hesitate to send a howler to set him straight.
A fanfiction could be about Snape's unspoken loyalty to Dumbledore. Despite their differences and the difficult tasks Dumbledore assigned him, Snape remained faithful. This could be explored through Snape's thoughts and internal monologues, showing his deep - seated respect for Dumbledore.
One common theme is self - discovery. As Albus travels through time, he often learns more about himself, his abilities, and his place in the wizarding world. For example, in many stories, he discovers hidden powers or aspects of his personality that he wasn't aware of before.
I also like 'Time - Traveling Severus: Altering Destiny'. This fanfiction takes Severus on a wild time - travel journey where he attempts to alter the fates of those he cares about. It has a lot of action and some great character development. You can really see how Severus evolves as a character as he bounces through different time periods.
One great fanfiction could be where Hermione travels back in time and tries to understand Severus better. She might see his early years at Hogwarts and how he was bullied. This could lead to her having a newfound respect for him and trying to change his fate in some way.