You can try looking on fanfiction - net. It has a large collection of various fanfictions, and there might be some related to 'natsu x silver fullbuster' there.
One popular 'natsu x silver fullbuster' fanfiction might be 'The Unlikely Bond'. It focuses on how their relationship develops in a unique magical setting. It shows their interactions and how they overcome challenges together.
One common theme could be adventure. Given the nature of the characters, they might embark on exciting quests together. Another theme might be friendship development that could potentially turn into a deeper relationship over time.
You can try some popular fanfiction websites like Archive of Our Own (AO3). It has a large collection of fanfictions, and you might be able to find 'natsu x silver lemon' ones there. Another option could be FanFiction.net, although the content quality can vary widely.
Lyon would also be a good match. Both are ice - mages, and they could have a friendly rivalry or collaborate on a difficult mission. They could exchange techniques and knowledge about ice magic, which would be interesting to read about in a fanfiction.
One good 'gray fullbuster x oc lemon fanfiction' might be 'Frosty Bonds'. It has an interesting plot where the OC has a unique connection with Gray. Another could be 'Shadowed Love' which delves deep into their relationship with some exciting twists.
Since 'lemon' fanfiction often crosses the line into adult content, we should focus on the proper characteristics of Gray in regular fanfiction. Gray is known for his stoicism, his rivalry with Natsu, and his strong sense of justice. These traits should be the focus rather than any improper aspects that might be in 'lemon' fanfiction.
First, get to know the characters well. Study Gray Fullbuster's personality, his backstory, and his relationships in the Fairy Tail series. For the OC, create a detailed character profile with a unique personality. Then, start with an interesting plot idea, like maybe the OC has a special power that Gray needs. Write in a way that shows their chemistry.
I'm not sure about the common themes in this specific fanfiction as I haven't read many of them. But it could potentially include themes of friendship evolving into love, adventure, and the discovery of new powers.
The main characters are Natsu and Grey Lemon. Natsu is likely to be a strong - willed and energetic character, while Grey Lemon might have some unique traits that make their relationship interesting.