The invisible friend could be a spirit from a long - lost magical realm. It befriends Snape because it senses his loneliness and his complex nature. As the story progresses, they discover that there is a connection between Snape's family history and this magical realm, and together they embark on a journey to uncover the secrets of his ancestry.
One idea could be that Snape's invisible friend turns out to be a manifestation of his repressed childhood self. It could help him face his past traumas and insecurities.
It could be other students at Hogwarts who sense something strange about Snape and his invisible friend. They might try to expose Snape's secret out of jealousy or because they think it's some sort of dark magic.
One idea could be exploring Addie's encounters with different historical figures in more depth. For example, how she influenced or was influenced by them during specific events. Another could be a story where she tries to find a way to reverse her curse in a new and unexpected way, perhaps with the help of a modern-day character who has some unique knowledge or ability.
One interesting fanfiction could be about Harry's invisible friend helping him discover hidden secrets in Hogwarts. Maybe the friend has special powers that normal wizards don't, like being able to see through ancient magic barriers.
A great plot could be that the goblin is a time - traveler. It has come from a future where Voldemort has won and is trying to change the past. The goblin teams up with Harry, using its unique goblin magic and knowledge of the future to give Harry an edge in the fight against the dark forces. They might have to travel to different magical locations and enlist the help of other magical creatures.
Another aspect could be the creativity of the author in weaving a story around such a concept. They might use vivid descriptions to bring out the emotions and scenarios in Snape's dreams. It could also be a way to explore the magical world from Snape's subconscious point of view, showing how his dreams might be influenced by the magic around him and his own magical abilities.
One plot idea could be that the characters discover the invisibility power has a time limit and they have to complete a mission before they become visible again. For example, they need to retrieve a stolen artifact from a heavily guarded place.
A great plot for a social invisible OC in Naruto fanfiction could be that they have a unique chakra ability that is both a blessing and a curse. It makes them stand out in a way they don't want, so they try to hide it. However, a powerful enemy discovers their secret and tries to use them for their own evil purposes. The OC then has to decide whether to keep hiding or use their power to fight back. Or, the OC could be a historian of the ninja world, but because they are so quiet and unassuming, no one realizes they hold the key to an ancient prophecy that could save the village from destruction.
One idea could be that the old friend resurfaces after many years and is somehow involved in a case Reid is working on. Maybe they have some hidden knowledge about the unsub that helps Reid solve the case while also reigniting their friendship.
One possible plotline could be that Snape, in his secret attempts to rescue Harry, starts to see a different side of him. Maybe during a dangerous situation in the Forbidden Forest, Snape saves Harry from a dark creature. As they spend time together afterwards, they begin to understand each other's pain and pasts, and slowly romantic feelings start to develop.
A plot could be where the two best friends are always there for each other. One day, they go on a trip together. During the trip, they get into a dangerous situation like getting lost in the woods. They rely on each other to survive. Through this shared experience, they see each other in a new light. They start to have romantic feelings. But they're afraid to admit it at first because they don't want to ruin their friendship. Eventually, they can't hold it in anymore and confess their love.