A more complex plot could involve Qrow and Ruby going on a mission together. They could encounter an ancient Grimm that is resistant to normal attacks. As they struggle to defeat it, they have to rely on each other's strengths and also face some internal conflicts. For example, Ruby might be too eager to prove herself and Qrow has to keep her in check while also dealing with his own self - doubts about being a good mentor.
One plot idea could be Qrow training Ruby in some special combat techniques that are unique to his own fighting style. This would allow Ruby to gain new skills and also strengthen their bond as family members.
One plot idea could be a gender - swapped Qrow in an alternate universe where she is a mentor to a new group of young hunters. She could have different relationships with the other characters, like a more motherly bond with Ruby. Another idea is that she is on a mission to uncover a conspiracy within the Huntsman academies, using her unique skills and charm.
One idea could be Qrow having to protect an endangered species all on his own. Maybe he discovers a unique Grimm - like creature that is on the verge of extinction and he has to fend off other threats while trying to understand it. Another could be that Qrow is part of a mission to save a group of people who are considered 'endangered species' in the RWBY world due to some new threat, and he has to use his skills and experience to lead them to safety.
One plot idea could be that Ruby discovers a hidden connection between her Silver - eyed powers and Ozma's ancient magic. Maybe she has visions that lead her to an old relic related to Ozma. Another could be that they team up to fight a new, powerful Grimm threat that is immune to normal Huntsman attacks, but Ruby's unique abilities combined with Ozma's knowledge can defeat it.
One plot idea could be Ruby and Winter teaming up for a special mission. Maybe they have to infiltrate an enemy stronghold. Ruby's speed and Crescent Rose could be combined with Winter's ice powers and combat skills for some epic fight scenes.
One idea could be Ruby trying to understand Salem's motives beyond just destruction. Maybe she discovers that Salem has a tragic past that led her to this path and Ruby attempts to find a way to redeem her. Another plot could involve Salem targeting Ruby specifically because of her silver - eyed powers and Ruby having to outwit Salem in a series of battles.
A possible plot for a fanfiction about Whitley and Ruby in RWBY could be that they are both chosen for a special task by Ozpin (or his successor). They are the least likely pair to be chosen together, but as they work on the task, they find out that they complement each other well. Whitley's knowledge of Atlas society and technology, combined with Ruby's combat skills and leadership, make them a formidable team. Along the way, they might face challenges from within the group that doesn't believe in their partnership, but they prove everyone wrong by achieving their goals successfully.
Another plot could involve Ruby and Arslan getting into a friendly competition. They could be competing in a tournament within the RWBY universe. This would show their different fighting styles and how they learn from each other during the competition. They might start off as rivals but end up as good friends.
One idea could be Ruby adjusting to her new cyborg body and the enhanced abilities it gives her, like super - strength or advanced weaponry integration. Another could be her facing discrimination from some in the RWBY world who fear or mistrust cyborgs.
One plot idea could be Ruby discovering she has werewolf abilities during a mission. She has to learn to control it while still fighting Grimm. Another could be that in a werewolf form, Ruby has enhanced senses that help her track down a powerful and elusive enemy. Or perhaps she forms a pack with some of her friends who also get werewolf-like powers and they have to protect Vale from a new werewolf - Grimm hybrid threat.
One idea could be Ruby discovering she has some cheetah - like abilities. Maybe she's faster than ever and has to learn how to control this new power. It could add an interesting dynamic to her combat style and how she interacts with her team.