Higanbana no Miko

alphinaud's heavensward and stormblood outfit has these lapel things and these glove things

y'shtola's heavensward and stormblood outfit has this gem on the collar

alisaie's heavensward and stormblood outfit has this red pin on the lapel and a red gem accent on the belt

lyse's early stormblood outfit has a smaller red gem on the blue gem necklace

and g'raha's outfit has smaller red gems on his big necklace.

i think these might be in reference to the post-arr quest Ancient Ways, Timeless Wants, where Tataru gets a bunch of "blood pearls" with the intention to make everyone charms with them. they're red pearls! these accents don't really look to be made of pearl, but... idk, it feels like a reference.

anyway, the outfits which were explicitly designed by Tataru (not counting the ones that were constructed by her but designed by someone else, like the stuff Y'shtola, Urianger, and Thancred have been wearing since Shadowbringers) that do not have these accents are pretty much just the ones intended for the WoL — neither the Scion Adventurer attire, the Scion Traveler attire, nor the Wayfarer's attire have red gem accents — but when presenting the WoL the Scion Adventurer set, Tataru does mention sewing the blood pearl charm into the lining, so it is explicitly in there, for the Adventurer attire at least.