Vaalingrade
Legend
This is probably why there aren't.Along with aasimar and tieflings, there should be modron-touched, slaad-touched, and, most importantly, fey-touched.
The representative creatures of Law and Chaos aren't things people relate to and want to play. Sure a lot of people have a fondness for Creepier Thomas The Tank Engine, and... accept the existence of disappointingly non-battletoads frog guys who even the lore says aren't supposed to be there, but how many want to play a dude flavored like them?
Fey would be a decent Chaos replacement if their actual alignment wasn't 'Fey' instead of the chaotic the stat block says, and there's.... really nothing interesting or compelling about Law. By necessity. The second you get a personality, the whole plane shifts.