UA Elven Subraces, is there any reason why Winged Elves did not get a +1 to a attribute?

4 elf Subraces: Avariel, Grugach, Sea Elf and Shadar-kai

There are 4 races from Unearthed arcana, avariel (winged elves), grugach (the wild elves of Greyhawk), sea elves, and shadar-kai (deathly servants of the Raven Queen)