Naruto himself would probably be one of the main ones. He's always been associated with powerful chakra use in the original series, and in this fanfiction, with only males using chakra, he would stand out even more. Another could be Sasuke. His chakra abilities are also quite remarkable, and he would be a key male character in terms of chakra use in this fanfiction.
Well, it could limit the power dynamics in the story. Since only males can use chakra, female characters might have to rely on other skills or abilities. This could lead to a more distinct separation between male and female roles, with males being the main fighters due to their chakra use.
One more plotline could be that Naruto uses his unique chakra to form a new kind of ninja art. Since he is the only male with this chakra, he has the potential to create something that has never been seen before in the ninja world. This new art could be a combination of his unique chakra properties and his own creativity. It might start as an experiment, but as he hones it, it becomes a powerful tool that not only helps him in battles but also changes the way ninja warfare is perceived. His friends might be initially skeptical, but as they see the potential, they join him in exploring and perfecting this new art.
One interesting fanfiction could be 'Naruto: The Chakra Prodigy'. In this story, Naruto's unique chakra as the only male with a special form of it leads him on a journey to discover ancient secrets. He faces new enemies and allies that are drawn to his distinct chakra signature.
Well, a possible plotline could be that the male characters feel left out and start a revolution to gain equal rights in chakra usage. Or perhaps a female ninja discovers a way to transfer her chakra to a male, but it has unforeseen consequences. Also, there could be a plot where the female - only chakra users are hunted by an outside force that wants to control this unique power source for themselves.
In some fanfictions, Naruto might use chakra strings in a similar way to how Sasuke uses his chakra to control his sword. He could send out his chakra in the form of strings to manipulate objects from a distance. For example, he could use them to pull weapons out of an enemy's hand or to tie up an opponent.
He might rely on his physical strength and martial arts skills. Naruto is known for his tenacity and determination. Without chakra, he could train his body to be extremely strong, like a super - athlete. He could use his speed and agility to dodge attacks and land powerful punches and kicks.
One example could be a fanfiction where male chakra users from different clans in Naruto come together to form a special task force. They could be on a mission to protect a secret chakra source that only male chakra can access. This would create interesting dynamics as they have to work together, despite their clan rivalries.
First, you need to do research on the Naruto universe, especially about how chakra works. Then, create interesting male characters with unique chakra abilities. For example, you could give one character the ability to manipulate his chakra into different elemental forms faster than others. Next, think of a good plot. Maybe a mystery about an ancient male - only chakra technique that has been lost.
If only females can use chakra in this fanfiction, the power dynamics would be turned upside down. The male characters we know, like Naruto and Sasuke, would be powerless in terms of chakra usage. Female characters would dominate in all aspects related to chakra - combat, healing, and jutsu creation. This would lead to a new social structure in the ninja world, where female ninja are at the top of the hierarchy due to their chakra - based abilities.