Speaking of, Fuujin is the only goddess to wear her Graeco-Roman peplos in the 'traditional' style, with the characteristic 'apoptygma' overfold. It also looks pinned, unlike the others that seem to tie theirs.

G-Spring has her peplos just tied over one shoulder instead of pinning it.

G-Sky's... think it's also a peplos, just tied or pinned at the back. A very short peplos. And it isn't quite rectangular either, but some of the Roman ones are kinda cut or sewn that way too (instead of being a simple rectangular bolt of cloth as is the case with older Greek peploi). Though, not that short.

G-Flame... looks like she wears a cropped Roman-style chiton. And a male Greek himation at her waist, wearing it like a skirt instead of a cloak. Oddly she seems to wear something different in post #4533007, where her top is tied at her back and doesn't have the neckhole and implied seams of the chiton (unlike all her other appearances). 'Skirt' also seems shorter and simplified, resembling a pareo more than a himation worn at the waist.

G-Forest... I don't know... hemmed dresses aren't usually found in Graeco-Roman wear, but I could have sworn I've seen forest nymphs depicted with a similar style of dress as hers.

G-Earth wears Japanese-style sarashi (other cultures have equivalents, but the way it's wrapped is sarashi-style), a shimenawa sash, and a... non culture specific loincloth-apron-skirt of some sort (though some Japanese male gods also wear something similar).

Raijin wears... I think a poncho thrown over a bandeau? Could be a Graeco-Roman style strophiae (something like that twisted cloth 'medieval' 'bra' you see in, say, some Elder Scrolls games) too. Not sure what she wears on her waist but from post #4533007 it looks like some kind of side-tie skirt.

(And while we're on the subject of Graeco-Roman underwear... Aphrodite was sometimes depicted with a literal gold chainmail bikini.)

Edit: Oh wait, some of the Roman mamillare/strophium (their adaptation of the Greek strophiae) practically look like a modern day bandeau, like what Raijin is wearing. And the Roman paenula is also similar to Raijin's poncho. Just need to crop it to chest length instead of their usual waist/knee.