Proposed:

In D&D, and in fantasy universes defined by the D&D alignment grid or anything similar, where each alignment gets its own race of Archetypical Exemplar Outsider Spirit Dudes – LE devils, CE demons, LG archons / celestials / whatever, you know the drill – the LN race always tends to be unpleasantly lame.  Formians suck, inevitables suck, modrons suck except when their inherent goofiness is being used for humor.  And it’s always for the same reason.  “Beep boop 100101100111, we have no individuality or personality, we march in lockstep in order to turn the universe into endless rows of featureless grey cubes” is a boring setup that is no fun to engage with, and the party line seems to be that cosmic-scale lawful neutrality has to be about that thing.

This is stupid.  Just as not every demon in the Abyss has to be Killfuck Soulshitter, because “chaos” and “evil” both mean a lot of different things, not every planar spirit of pure law has to be about rows of grey cubes, because “law” means a lot of different things too.  (And, yes, in official materials way too many demons are Killfuck Soulshitter, but…one problem at a time.)  In particular, “lawful” shouldn’t translate to “boring” any more than “chaotic” should translate to “wacky.”

For your new archetypical LN planar race, I propose: the fey.  Like, classic Eurofae-type fey, the ones you know.

Seriously!  They are creatures who devote the entirety of their being to living by, to being defined by, their codes and their oaths.  They are sworn to arbitrary rules that may not make any sense to anyone else, and that may not advance their interests in any way, but come what may they will never ever break those rules.  They are, famously, indifferent to good and evil alike. 

…mumble grumble, the D&D thing where fey are always chaotic makes no sense at all, unless you’re just going by the heuristic that says “lithe and emotional = chaotic, blocky and stolid = lawful.”