He would probably be extremely fast, able to move at speeds that would shock his opponents. His attacks would become more unpredictable as he could quickly close the gap between him and his enemies.
If Naruto were blessed by the speed force in a fanfic, it would completely change his fighting style. He could quickly close the gap between him and his foes, and his rasengan would be delivered in a blink of an eye. Also, his ability to gather information on the battlefield would be enhanced as he could zip around to different locations rapidly.
One possible fanfiction could involve Naruto being transported to the Young Justice universe and somehow getting connected to the Speed Force. Maybe he gains super - speed abilities and has to learn how to control them while also dealing with the threats in the Young Justice world. He could team up with the Young Justice characters, like Robin or Kid Flash, and use his ninja skills along with his new speed powers to take on villains.
Well, he would be super fast, for sure. He could zip around the battlefield so quickly that his enemies wouldn't be able to keep up. He might be able to use his new speed to perform his jutsu even more effectively, like hitting multiple targets in an instant with a Rasengan.
Naruto could fit in by having his own unique take on the Speed Force. Maybe his 'Nine - Tails' chakra gives him a special connection to it. He could use his speed to perform his ninja techniques even more effectively, like using Rasengan at high speeds. And he could form bonds with the Young Justice characters based on his shared sense of justice.
Ruby would be a likely candidate. She's already known for her speed and agility in combat. If she were to be affected by the Speed Force, it would enhance her existing abilities to a whole new level. She could move so fast that she becomes almost invisible to her enemies, and her scythe attacks would be even more deadly with the added momentum.
Peter Parker in the context of the Speed Force could be really interesting. The Speed Force is often associated with speedsters like The Flash. If Peter Parker were to be connected to it, perhaps he could gain super - speed in addition to his spider - powers. This could make him even more formidable in fighting crime in New York. He could use his speed to quickly web up villains or reach the scene of a crime in an instant.
The Speed Force in Young Justice fanfiction can also be a source of conflict. Maybe the Speed Force starts acting erratically and causing problems in the world. The Young Justice team has to figure out what's wrong with it. Is it being manipulated by a villain? Or is it a natural imbalance? This could lead to a complex and exciting storyline as they search for answers and try to restore the Speed Force to its normal state.