Sylvari - Fae
Most likely they both stole heavily from actual Fae lore and old tropes about them (like the plant-based clothing). From what I can see from the wiki the Summer/Winter courts are outright called Seelie/Unseelie, which are the folklore that the Dreamer/Nightmare concept is based off of.
GW2 puts some interesting dressings on the Sylvari but when you get down to it they’re fairies, and fairies are a very old and expansive concept. You find ’em everywhere.
Arabelle Jones | Human Engineer
Stormbluff Isle
Kingdoms of amalur came out AFTER the sylvari I redesign had been released, neither of them copied the other, both games will have been in development for years.
As the person above me suggests they both follow pretty conventional tree-folk/fae designs.
The fae in KoA are really really ugly though if you ask me. The Sylvari on the other hand are gorgeous.
I’ve seen many concepts of tree-people/fairies myself on some arts and etc, but it’s
kinda strange when games released with pretty small interval, had almost the same
setting and almost same concepts of Fae/Sylvari just with different names, tho it’s
first time I encounter this kinda race in a game.
As for uglyness, I don’t really find any differnce between them in KoA or GW2 since
games are almost on the same level of graphics + as KoA being a singleplayer and
mostly storybased, they showed Fae in more depth than it is in GW2 IMO.