Grimdark and noblebright are the perfect sub-genres for readers who either want a less 'bright' book, but not quite Stephen King horrifying and dark. Or a fun book that is not quite Harry Potter light.
Ladies and gentlemen, I present Grimdark fantasy and noblebright fantasy.
“Grimdark is a subgenre or a way to describe the tone, style or setting of speculative fiction (especially fantasy) that is, depending on the definition used, markedly dystopian or amoral, or particularly violent or realistic.”
Because grimdark is not horror or dark fantasy, its more 'gray' atmosphere result from it to have almost a dystopian apocalypse atmosphere, despite being a fantasy sub-genre. Good examples of grimdark fantasy include books such as the incredibly famous and popular A Song of Ice and Fire by George R. R. Martin, Prince of Thorns by Mark Lawrence, and The Series of Unfortunate Events by Daniel Handler.
If you really think about it, I think we all have this feeling in our guts that we all have to at least come across books like this at least once. But the fact that we can't even identify them shows how truly underrated they are, compared to the others like the classic light and dark fantasy.
Grimdark, in my opinion, is a hit or miss. Because this genre is also not exactly bright or dark, that combination and how a story can be written through that genre makes it something completely different. In other words, if done well, it can bring great depths, character developments, and great story climaxes. But if done not well, it'll become too slow for many readers, bland, and overly confusing.
There's just that little tiny gray area that if the author manages to hit, he or she would absolutely ace the genre.
Noblebright is a 'brighter' fantasy than grimdark, but like grimdark with dark fantasy, it's not as 'bright' as light fantasy. And that combination (like grimdark, again), made it unique in is own way.
"Noblebright fantasy doesn’t necessarily exclude dark themes, but the slant of the narrative or the nature of the characters can be different. There is room for idealism, the possibility of redemption (in its broadest sense) and the narrative is not unrelentingly bleak."
Good examples of noblebright fantasy are The King’s Sword by C.J Brightly and A Threat of Shadows by JA Andrews. Noblebright itself (excluding fantasy), specifically states that it's "The notion that the actions of one person can make a difference, that even if the person is flawed and opposed by strong forces, he can (and wants to) rise to heroic actions that, even if they may cost him his life, improve the lives of others." - Noblebright. So noblebright fantasy is basically a sub-genre when in a not so-bright situation, a character or person must make the best of it.
Noblebright unlike grimdark is quite new and unknown to the reader's world. I really hope that can change, and noblebright can more out there, just like grimdark.
Either way, keep this in mind next time you read a fantasy, or just a noblebright book. Because it's so underrated, there are many books out there that might be noblebright, just that no one knows it because they have no idea what the genre is. You can change that by helping sort books into noblebright if they are.