Sure, there are pieces of fanfiction focusing on a Hulk - Black Widow romance. In these stories, the writers usually play with the idea of the contrast between the Hulk's brute strength and Black Widow's agility and intelligence. It could be a story where the Hulk protects Black Widow in a new and unexpected way, leading to feelings developing between them. They might also explore how their different backgrounds in the Marvel universe could bring an interesting dynamic to a romantic relationship.
Another theme is the power of friendship. They come from very different backgrounds, but in fanfiction, they often form a strong bond. They support each other in battles and in personal growth. Like when Black Widow is in a tough situation and the Hulk comes to her rescue, showing that they have each other's backs.
Another theme is redemption. Sometimes the Hulk is portrayed as a character seeking redemption for the destruction he's caused, and Black Widow helps him on that journey. It's about how they can find a new purpose together. A lot of fanfictions also play with the idea of them being outsiders in the Avengers group, and how they form a special bond because of that.
I really liked 'Green and Black'. In this fanfic, it shows a scenario where Black Widow has to protect the Hulk when he's in a vulnerable state. It's full of action and also some really tender moments between the two characters as they learn more about each other.
A frequent theme is 'partnership'. They are both part of the Avengers, and fanfictions often explore how they work together in different situations. For example, in some stories, they are the last line of defense against a powerful threat. Also, the theme of 'forbidden love' can be found in some 'the hulk and black widow fanfiction'. Their different natures and the potential complications within the Avengers team can make a love story between them seem both exciting and challenging.
Yes, there might be some out there. Fanfiction often explores various creative and unexpected scenarios, and a 'Hulk and Black Widow pregnant' concept could be part of the wild ideas in the fanfiction world. You can try searching on fanfiction - specific websites like Archive of Our Own or FanFiction.net to see if such stories exist.
In the comics, their relationship can be described as complex and not always straightforward. Sometimes they work together on missions, and there are moments of mutual support and understanding.
One common theme is the idea of the 'beast and the beauty'. The Hulk's powerful and sometimes uncontrollable nature contrasted with Black Widow's allure and grace. Another theme could be redemption. Maybe the Hulk finds a sense of peace and normalcy through his relationship with Black Widow. And also, there's often the theme of trust. Since both characters have had difficult pasts, they learn to trust each other in a romantic context.