Someone please tell me the name of these tights/socks!

Those are Black Ribbon Socks from one of the past Mission Passes.

@AndrlCh It won't help getting this item, but isn't this Laced Knee Socks: Black?

I usually won't double check your answer, but somehow it happened this time

@Fiona-Respha You are right, that is the NA name. Since I posted from my phone, I just went off of memory with the intention of double checking in-game when I got the chance, but it totally slipped my mind.

All right, if we're talking about the same thing, that's fine.

Found a video showing this, looks like mission pass season 2, tier 6 item.