One common theme is self - discovery. Beast Boy often has to figure out his own feelings and how he really feels about each person in the harem. Another theme is friendship within the harem. Even though there are romantic elements, the characters also form strong bonds of friendship. For example, they might support each other during battles or tough times.
One idea could be that Beast Boy discovers he has admirers from different dimensions. Each girl from these dimensions has a unique power and personality. For example, a water - controlling mermaid - like girl who is shy but drawn to Beast Boy's kind nature. Another could be a girl from a magical realm who is a powerful sorceress and sees Beast Boy's potential in a different way than others.
First, you should do some research on Beast Boy's character. Know his powers, his personality traits like his sense of humor and his loyalty. Then, think about the type of girls you want in his harem. Decide if they'll be from the same universe or different ones. After that, start with an interesting opening scene, like Beast Boy in the middle of a mission where he meets the first girl who will be part of the harem.
One popular Beast Boy harem fanfic is 'Beast Boy's New World'. It has an interesting plot where Beast Boy finds himself in a situation where multiple characters are attracted to him in different ways. Another one could be 'Beast Boy's Harem Adventures' which focuses on his interactions with a group of characters in a harem - like setting, filled with humorous and heartwarming moments.
I think you might be referring to some fan fiction scenarios. But in the original Teen Titans comics or animated series, Beast Boy doesn't have a harem.
Starfire could also be part of it. Her bubbly and positive personality would contrast with some of the other characters. She might be the one who always tries to cheer up the group and is very affectionate towards Beast Boy.
The 'beast boy sad fanfic' could be a creative exploration of the character in a more vulnerable state. It may attract readers who are interested in the emotional depth of the character. It could also serve as a way to expand the existing narrative of the Beast Boy's story in the original source material. By focusing on his sadness, new aspects of his personality and relationships can be uncovered and developed.
One great 'Starfire x Beast Boy fanfic' is 'A Different Kind of Bond'. It shows their relationship developing in a really unique way. The story has a lot of heartwarming moments as they learn more about each other.
I'm not sure if there is a widely known 'beast boy totrued fanfic'. You could try searching on fanfic platforms like Archive of Our Own or FanFiction.net. They have a large collection of Teen Titans - related fanfics and might have something with a similar title.
Some interesting Beast Boy Beast fanfic ideas could involve time - travel. He could go back in time and meet his younger self, and through that encounter, he learns something important about his growth and development. There could also be a fanfic where he is the only one left in the Teen Titans and has to figure out how to carry on their legacy all by himself. This would really show his character's strength and determination. Additionally, a fanfic that explores his dreams and nightmares, and how his powers might be affected by his subconscious thoughts, could be really fascinating.