Love and romance are also likely themes. Writers may depict the development of romantic feelings between Yelena and Pieck. This could involve slow - burn romances where they gradually realize their feelings for each other, or perhaps more fast - paced love stories where they fall in love quickly due to some extraordinary circumstances. There could also be themes of sacrifice, where one of them is willing to sacrifice something for the other in the context of their relationship.
Well, you can try searching on fanfiction platforms like Archive of Our Own. There might be some great 'yelena x pieck fanfic' there. Just use the search function and type in the relevant tags.
Fanfiction about Eren and Levi kissing can be quite interesting. It might explore a different side of their relationship. Some fanfictions in this regard could be about a moment of emotional intensity between them, where the kiss represents a deep connection that goes beyond their usual interactions in the original story.