Regret is a main element. The characters usually regret a past action or inaction. Another element is hope. There's always the hope for that one more time and chance. And the setting often plays a role too, as it can be the backdrop against which the missed opportunity occurred.
Well, 'one more time one more chance story' could be many things. It might be a story about a person who let someone special go and then realizes later how much they miss that person. They wish for one more time to be with them, one more chance to make things right. It could also be about a missed business deal and the protagonist's yearning for one more time to pitch their idea, one more chance to succeed.
One interesting fanfiction could be about Chopper's further adventures in a new, uncharted island where he discovers a unique type of medicinal plant that has strange effects on the Straw Hat crew. Another might be a story where Chopper has to take on the role of the ship's doctor in a really difficult situation when all the other crew members are incapacitated. There could also be a fanfic that focuses on Chopper's past, delving deeper into his time before he joined the Straw Hats and how he coped with being alone as a reindeer in a human - dominated world.
Not having read 'do it one more time novel', it's a mystery regarding its genre. However, if the 'do it one more time' refers to a character taking an action repeatedly, it could be a thriller where the repeated action builds tension. It could also be a historical novel if the repeated action is related to a historical event or a cultural practice. There are just so many possibilities without more details about the novel.
I'm sorry, I'm not familiar with a specific 'one more time story'. It could be a very unique or personal story, or perhaps a relatively unknown piece of work.