One good one might be 'Kurenai's Hidden Feelings' where it shows her internal struggle with her feelings for Naruto in a very sweet way. It has some really cute interactions between them.
One scenario could be that Naruto, while training with Kurenai, starts to notice her in a different way. He might be drawn to her confidence during combat instructions. Another could be that Naruto accidentally stumbles upon Kurenai in a vulnerable moment and that moment of seeing her in a new light sparks a crush.
Yes, in some fanfictions, Naruto is depicted as having a crush on Kurenai. Fanfiction allows for creative interpretations of characters' relationships, and this is one such interesting take.
A plot could also be centered around Naruto asking Kurenai out on a date. He would be really nervous and might ask for help from his friends. His friends could give him all kinds of advice, some good and some really bad. And when he finally does ask her, Kurenai's reaction could be a mix of surprise and amusement. This could lead to a series of events where they get to know each other better on this 'date' and explore their relationship further.
One possible plot could be that Naruto, as a young father, finds himself drawn to Kurenai's strength and wisdom. Maybe he sees in her the qualities he wishes to instill in his own child. He starts to have these unexpected feelings while they are working together on some mission or training the new generation of ninja. Kurenai, at first, is oblivious to his crush but eventually notices the change in his behavior towards her.
I'm not sure if there is a specific fanfic with exactly that plot. There are a lot of Naruto fanfics out there, but this particular combination might be quite rare. You could try searching on fanfic - specific websites like Fanfiction.net or Archive of Our Own to see if such a story exists.
One idea could be that Naruto tries to impress Anko with his new jutsu skills. He might show off in front of her during a training session. Since he has a crush, he'll be a bit clumsy about it but also very determined.
Well, in such a fanfic, Naruto might start off being really shy around Kurenai. He could constantly find excuses to be near her, like asking for advice on ninja techniques even though she's not his usual trainer. Maybe he would blush every time she looks at him. And he'd probably be daydreaming about her during his free time.