In 'oc speed force fanfiction', an interesting plot could involve an OC who is not from our dimension but is brought here by a malfunction in the Speed Force. This OC has to adapt to the new world while also trying to find a way back home. Along the way, they form an unlikely alliance with a local speedster and together they face threats that are related to the misbehavior of the Speed Force.
One idea could be an OC who discovers they have a unique connection to the Speed Force that allows them to time - travel in a different way than the Flash. For example, they can visit alternate timelines related to speedsters. Another idea is an OC using the Speed Force to create speed - based constructs, like swords or shields. It would add a new dimension to their powers in combat.
Well, your OC could be a villain in a 'oc speed force fanfiction'. They might be a scientist who figures out a way to manipulate the Speed Force for evil purposes. Maybe they use it to slow down time for everyone else while they move at normal speed, causing chaos. Or they could steal the speed of other speedsters, leaving them powerless.
One idea could be a character from RWBY gaining the power of the Speed Force and using it to outmaneuver their enemies in combat. For example, Ruby could use the speed to create afterimages and confuse Grimm while she attacks them from unexpected angles.
Well, you could create an OC fanfiction where the OC is a scientist who discovers a new way to combat Infernals that doesn't involve burning them. This OC might be initially rejected by the Fire Force but then proves their method's worth. Also, an OC with a special connection to the Adolla Burst could be interesting. Maybe they can communicate with the spirits of the Infernals or have visions related to the Adolla realm, which would lead to new adventures and revelations within the Fire Force world.
One idea could be Percy Jackson somehow gets connected to the Speed Force. Maybe during a quest, he stumbles upon a portal or an ancient artifact that links him to this powerful force. He could then gain super - speed, but struggle to control it at first. His demigod powers might interact in strange ways with the Speed Force, like his water - based powers could be enhanced when he moves at high speeds, creating some kind of water - speed hybrid attacks.
A plot idea could be that a portal opens between the My Hero Academia world and the DC universe where the Speed Force exists. A hero from MHA gets sucked into the DC world and has to learn to control the Speed Force to get back. Along the way, they meet DC characters and learn new ways to use their speed - based powers.
One idea could be exploring the backstory of Rey's parents in more detail. Maybe they were part of a secret Jedi order that was in hiding. Another could be a story about Finn's life before he defected from the First Order, like his training and relationships with other stormtroopers. Also, a fanfiction could focus on Kylo Ren's struggle with the light side of the Force that he tries to suppress.
You could also write about Naruto forming a special force within the Hidden Leaf Village. This force would consist of some of the most talented ninja from different clans. They would be trained by Naruto himself to face threats that are beyond the capabilities of the regular ninja forces. It could explore how Naruto's leadership skills and his understanding of different ninja abilities would help in creating a formidable team.
You could write a fanfiction that delves deeper into the relationship between Arthur and Shinra. Maybe they get into a big argument over their different approaches to being a hero. Shinra believes in using his powers for the greater good in a more practical way, while Arthur is all about living out his 'knight in shining armor' fantasy. This argument could lead to them going their separate ways for a while, and then having to come back together to face a powerful Infernal that neither of them could defeat alone.
The OC could be a scientist who is working on a new way to control the Infernals without having to kill them. Tamaki is assigned to protect the OC as there are those who oppose this new method. As they spend time together in the lab and during field tests, Tamaki becomes fascinated by the OC's intelligence and dedication. The OC, in turn, is charmed by Tamaki's positive attitude. They might face opposition from within the Fire Force, but their relationship and the OC's research continue to progress.
One interesting 'Harry Potter Speed Force' fanfiction could be one where Harry discovers the Speed Force during a dangerous encounter in the Forbidden Forest. He uses its power to outrun dark creatures, like dementors. Another might involve Hermione using her knowledge to study and harness the Speed Force for the good of the wizarding world, perhaps to quickly transport medical supplies during a war. And there could be a fanfic where Ron accidentally stumbles into the Speed Force and has to learn to control his new - found speed while also dealing with his insecurities in the wizarding world.
One interesting concept could be Naruto being able to access the Speed Force to quickly move between the Hidden Villages. This would give him an edge in battles and also in delivering important messages.