I've found LLM's to be extremely helpful in naming and general function/API design, where there a lot of different ways to express combinations of parameters.

I know what seems natural to me but that's because I'm extremely familiar with the internal workings of the project. LLM's seem to be very good at coming with names that are just descriptive enough but not too long, and most importantly follow "general conventions" from similar projects that I may not be aware of. I can't count the number of times an LLM has given me a name for a function that I've thought, oh of course, that's a much clearer name that what I was using. And I thought I was already pretty good at naming things...