One good 'OC Gremory Neglected' fanfiction could be 'The Lost Gremory'. It focuses on an OC in the Gremory family who has been overlooked and their journey to find their place. Another might be 'Gremory's Forgotten One' which delves into the emotions of the neglected OC as they face various challenges within the family dynamic.
Some niche fanfiction communities or forums dedicated to the relevant fandom might also be a good source. Members often share their own fanfictions or recommend ones they've read. For example, if there's a specific forum for the series that the Gremory concept is from, check there for any 'OC Gremory Neglected' fanfictions.
It could be that some of the neglected characters from Naruto, like Rock Lee for instance, are made main characters in this fanfiction and are paired with a Gremory character. Maybe a Gremory character who also has been somewhat overlooked in their own series. This would give a new perspective and new storylines to explore.
Well, in such a fanfiction, the interesting part could be the unique crossovers. Maybe it combines the Naruto universe's ninja skills with the Gremory's magical elements in a really unexpected way. It might also explore new character relationships that we don't see in the original works.
The plot might involve Naruto being shunned by the Gremory family or their associates. This could lead to Naruto having to find his own path. He could encounter other outcasts or those who also feel neglected. Together, they might form an alliance to change the perception of the Gremory family towards them or to simply make a place for themselves in this world that seems to not want them.
A common theme is self - discovery. The male oc often has to figure out his place in the Gremory world and what his powers or abilities truly mean. Another theme is friendship. He usually forms strong bonds with members of the Gremory family or other characters in that realm.
You can start by giving the OC a unique backstory. For example, if they are a human, they could have had a strange encounter in their childhood that awakened a latent power. This backstory can shape their personality, like if they had a tough childhood, they might be more cautious or distrustful at first.
One interesting story could be about an OC who has a unique power that helps the Gremory group in a new and unexpected way. For example, an OC with the power to manipulate time slightly, which they use to gain an edge in battles against their enemies.
There's 'Male OC in the Gremory Realm' which is quite interesting. The male oc in this story has to overcome various challenges in the Gremory world. He forms unexpected alliances and has some really cool battles. It's a great read for those who like this type of fanfiction as it also delves into the politics of the Gremory society.
One idea could be that the OC is a new transfer student to the school where Rias Gremory is. They accidentally discover a hidden power within themselves that Rias is interested in. So she takes the OC under her wing, and as they train together, a deep bond forms between them.