One great 'Ben 10 Ben x Gwen Fanfiction' is 'Parallel Bonds'. It explores their relationship in an alternate universe where they have to work together against a new kind of enemy. The story is full of action and also delves into their emotional connection.
You can try looking on some popular fanfiction websites like Archive of Our Own (AO3) or FanFiction.net. However, make sure to abide by the rules and guidelines of these platforms.
I'm not sure specifically which 'Ben x Gwen lemon fanfiction' are popular. However, in general, fanfiction often explores different relationships and scenarios. It could involve adventures they go on together in an alternate universe, or how their relationship might develop in a more romantic and emotional way. But it's important to note that some fanfiction might not be in line with the official canon of the source material.
Some specialized fanfiction communities or forums might be a good place to look. For example, certain sub -reddits dedicated to the fandom might have users sharing their own gwen x ben lemon fanfictions or know where to find them. Also, Tumblr can be a source. There are often bloggers who post about or link to such fanfictions on their pages.
One popular gwen x ben lemon fanfiction might be 'The Unspoken Bond'. It delves into the complex relationship between Gwen and Ben in a very engaging way. Another could be 'Gwen and Ben: A Different Path' which takes their relationship in a new and interesting direction.
I don't recommend delving into the themes of lemon fanfiction. But for regular Ben and Gwen - related fanfiction, themes can be things like loyalty. They are always there for each other during their battles against aliens. Another theme could be their evolving relationship as they get older and face more complex situations in the series. Also, their individual character development, like Ben becoming more responsible and Gwen getting stronger with her powers, are often explored.
One common theme is growth. Both Ben and Gwen grow as individuals and in their relationship. Another theme is friendship, as their bond is often a central part of the stories. Adventure is also a big theme, since they are from the Ben 10 universe and usually go on exciting adventures together.
I'm not sure if there are specifically 'good' ones in the sense of 'lemon' fanfics as they often involve inappropriate content. It's better to focus on non - explicit fanfics that explore the relationship between Ben and Gwen in a more positive and family - friendly way.
I'm not really into the lemon fanfiction area as it often involves inappropriate content. However, you can try searching on some well - known fanfiction platforms like FanFiction.net or Archive of Our Own and use the tags related to 'Ben 10', 'Ben', 'Gwen' to find appropriate stories that might be in the vein of what you want.