Parmandur
Book-Friend, he/him
"Perhaps the most surprising reveal, but not entirely unwarranted; Pureblood Yuan-ti have always been the most "human" of Faerun's snake-folk, and did in fact get a PC writeup in the Serpent Kingdoms sourcebook for that setting back in 3e. As for their crunch... put it like this; there's powerful, there's overpowered, and there's "holy , what were you ing thinking, WoTC?!" Yuan-ti fit pretty firmly into that last category: +2 Cha, +1 Int, Darkvision, Medium with Normal Speed, Poison Immunity, Poison Spray cantrip spell-like-ability, Suggestion 1/day, permanent Animal Friendship (snakes only) and, the cherry on top, "Magic Resistance: You have Advantage on all saving throws caused by spells and magical effects". Sweet crunchy christ..."
I found this on the internet. I was pretty close in my guess. I was right about Poison Spray being a full cantrip, Poison Immunity, Darkvision, Animal Friendship with snakes only. I wrong but close on suggestion, I thought it would be once per short rest, but it got nerfed to once per day, and I thought they'd drop magical resistance, but the Purebloods get it.
Still they over state their case at it being over powered. No physical stat bonus, poison spray is one of the weakest combat cantrips, dealing poison damage the worst form of damage you can deal because alots of stuff is immune to it, and having poor range, animal friendship with snakes is so narrow its going to be incredibly situational, darkvision is common in 5e races, suggestion is only once per day. Poison Immunity and Magic Resistance are good, with without these the Purebloods would be weak. Absolutely balanced in my opinion.
Several of those abilities look like pure ribbons: animal friendship with snakes will have it's uses, but is not a big thing, mainly flavor.
I have this idea now for a Pratchett-esque Yuan-Ti immigrant subculture in the big cities. Sure, the folks over in Snaketown/Little Najara aren't that into the old time snake cults, just looking to make a living and raise their families. However, there might be a mafia like presence in that part of town...