One common theme is adventure. Since Gohan has his Beast form, they might go on adventures together fighting enemies. Another theme could be romance, exploring their relationship deeper.
Most people would probably be very critical. The Beauty and the Beast is a well - loved story with certain values, and this kind of fanfic would seem to violate those values. It could also face a lot of pushback from the community for being inappropriate and not in line with the spirit of the original work. Moreover, it might be considered offensive to many who view the characters in a particular way.
Well, another place could be some dedicated Dragon Ball fan forums. There are often sections where fans share their own fanfictions or recommend good ones. Some popular Dragon Ball forums might have threads specifically about Videl and Gohan Beast's relationship in fanfiction form. You could also ask around in those forums if you can't find what you're looking for right away.
There were a few novels that could be recommended, including Those Years Living in the Future World of Dragon Ball, If Dragon Ball, Latiz took Gohan away, and The Strongest Sun Gohan of Dragon Ball. These novels all used Gohan as the protagonist, telling his growth and adventures in the Dragon Ball world. These novels might satisfy your need for Gohan to be the protagonist.
Pregnant women's reactions referred to the appearance of a series of uncomfortable symptoms due to changes in hormone levels and mental imbalance in the early stages of pregnancy. These symptoms included dizziness, fatigue, loss of appetite, sensitivity to greasy food, nausea, vomiting, and so on. The degree of response of pregnant women varied from person to person. Some pregnant women had a strong reaction, while others had almost no reaction. Early pregnancy reactions usually begin to appear 6-8 weeks after pregnancy. In most cases, they will disappear naturally around 12 weeks of pregnancy. Pregnant women could alleviate their reactions by maintaining a happy mood, eating a light diet, and exercising appropriately.