One plot twist could be that the pregnancy is not a normal biological one but is caused by some sort of magical or alien influence. Another could be that Steven tries to keep it a secret at first, but then it gets accidentally revealed in a really awkward or dangerous situation.
Well, a possible plot twist is that the pregnancy is part of a prophecy that no one knew about. Or perhaps the baby has some special powers that start to manifest even before it's born, which causes all sorts of chaos and confusion. Also, there could be a plot twist where the pregnancy is actually a false alarm, but in the process of thinking he was pregnant, Steven learns a lot about himself and his relationships.
One interesting plot twist could be that a previously thought - to - be - evil gem actually has a noble reason for their actions. For example, a gem who was fighting against the Crystal Gems might be trying to protect a hidden colony of gems that would be in danger if the war ended a certain way.
One interesting plot twist could be that Steven discovers that he is the one who unknowingly created the time loop in the first place. Maybe his overuse of his powers in a particular situation disrupted the time - space continuum, leading to the loop.
A possible plot twist could be that one of the Avengers, say Hulk, is actually a long - lost Gem. His transformation into the Hulk could be related to some dormant Gem power within him. This would completely change the way the other Avengers and the Crystal Gems view him.
In a 'Steven Universe Sapphire Pregnant' fanfiction, perhaps the pregnancy is unexpected. Sapphire could start having premonitions about the future of their unborn child. The story might focus on how the other characters in the show react to the news. Some might be overjoyed, like Pearl who loves new life among the Gems, while others could be more cautious, thinking about the potential dangers in their world.
Well, in a 'Steven Universe Garnet Pregnant' fanfiction, the plot could start with Garnet sensing a new life within her. This could lead to a series of events where she has to protect this new life from the threats that the Crystal Gems usually face. Maybe she has to go on a journey to find a safe place for the baby. Along the way, her relationship with the other Gems, especially Ruby and Sapphire, could be explored in a new light as they also prepare for the new addition to their family.
A really interesting plot twist in these fanfics can be when Spinel gets corrupted again, but this time Steven has to find a completely different way to heal her. It challenges his usual methods and tests their relationship. Another plot twist could be that Spinel starts to have dreams or visions about Steven's future, and she has to decide whether to tell him or keep it a secret. This can lead to a lot of internal conflict for Spinel and also affect her relationship with Steven in unexpected ways.
One idea could be that Lars and Steven go on a space adventure together. They might encounter new gem species and have to work together to solve problems. For example, they could find a planet where the gems are in a civil war, and Lars and Steven use their unique skills to bring peace.
A really interesting plot twist could be that Steven goes back in time and discovers that the Diamonds had different motives than he originally thought. Maybe they were being influenced by some other force in the past, and by going back, he uncovers this mystery. Also, he could find out that some of the things he thought were his friends' ideas were actually planted by an outside source long ago. This would completely change his understanding of the relationships and history in the Steven Universe world.
A possible plot could be that Lapis is pregnant, and it's a result of some sort of experiment gone wrong in the Gem world. She initially fears for the safety of the unborn and struggles with her own identity as a mother - to - be. As she progresses through the pregnancy, she forms unexpected bonds with other characters who also have their own stories related to creation and family in the 'Steven Universe'. This could lead to a story of self - discovery, acceptance, and the power of friendship as they all face this new situation together.
A more emotional plot could be an OC who was once part of the Homeworld gems but defected. They have a lot of guilt and self - doubt because of their past actions. In the fanfiction, they try to make amends by helping the Crystal Gems. But they constantly fear that their old allies will come after them. This internal struggle and their journey of redemption could be a really interesting story.