Butterbelle

ButterBelle is the femslash ship between Buttercup and Princess Bluebelle from The Powerpuff Girls fandom.

Canon
In the episode "Once Upon a Townsville", while being chased by a dragon, Princess Bluebelle falls into a magical well which transports her to Townsville. There, Buttercup is arguing with her sister, Blossom about clouds. Buttercup says that if they were made of water, they would fall from the sky. Bluebelle falls from the sky and lands in her arms. "Ooh, clouds are pretty!" says Bubbles. The dragon follows Bluebelle but the girls are able to get rid of it quickly by Bubbles saying "Bad dragon!"

They lie her down on a bench, Buttercup believing her to be dead. Bluebelle awakens and Buttercup mistakes her for a Zombie. Bluebelle, thinking that Buttercup is a prince, kisses her, before realizing that she is not a prince. Buttercup panics, thinking she has been kissed by a zombie. Their relationship is not explored throughout the rest of the episode though.

She then introduces herself through song. She proceeds to make many attempts to get a prince to save her such as jumping into a volcano, taking a raft off a waterfall and trying to eat poisonous apples. Buttercup and her sisters end up saving her every time. The girls then get captured by the dragon but are then saved by Bluebelle.

Fanon
Due to the kiss between the two, despite the age gap between them, many people have shipped them together. The ship is relatively small. Some fanart has been made. As Bluebelle only appears in one episode, the ship is not extremely well known. The two do not have any strong connections, apart from the kiss. However, it is known for being one of the few same-sex kisses in children's cartoons. The ship is controversial among some though since Buttercup is a child and Bluebelle is a fully grown woman.

Fandom
https://www.youtube.com/results?search_query=buttercup+x+bluebelle