There may be good options coupled with agents like Claudes Front End Design skill, I haven't used it.

I have been using Magic Patterns which is very good at generating initial prototypes, especially when driven by an agent familiar with it's facilities and constraints.

I assume the service is just a wrapper plus scaffolding but I like it. You have to push it though to get anything particularly creative but it's good at standard front end designs.

https://www.magicpatterns.com/

That's not necessarily what you're after because I only use it for piloting stuff, not for adhoc feature addition and fixes.