is there any official precedent for Elven Barbarians in the Forgotten Realms?
Asking for a friend, who is me. My FR-specific minutiae is rudimentary at best. But, looking through Mordenkainen's Tome of Foes, there are a few potential hooks.

The first I see is the Seldarine deity Shevarash, god of vengeance, loss, and hatred. That sounds like a patron of elf barbarians. 1/-

— Dan Dillon (@Dan_Dillon_1) April 27, 2020

Further, look at the section on Arvandor, pg 48. “The native elves are boisterous, tempestuous, and ready to draw blood over the slightest insult or lapse of tradition.”

It also says reincarnated elves sometimes carry memories of life in Arvandor. Seeds of rage there. 2/-And finally, since you mentioned Wild Soul, Eladrin are an easy connection to that Primal Path. The unfettered extremes of emotion blended with unpredictable magic of the Feywild plus elves in tune with the plane = go time rage magic. 3/3

— Dan Dillon (@Dan_Dillon_1) April 27, 2020

3rd level spells are a paradigm shift. In one gamer's opinion, you don't hit another shift of that magnitude again until you get 9th level spells.

— Dan Dillon (@Dan_Dillon_1) April 21, 2020

So true. I feel like scrying and long-range teleportation magic are notable game-changers along the way, too. Those strike me as more of a macro change. 3rd level with the sudden jump in, for example, area damage spells affects things on an encounter-to-encounter basis.

As an example, encounter design is incredibly different pre versus post fireball/spirit guardians.

— Dan Dillon (@Dan_Dillon_1) April 21, 2020

Travel encounters disappeared, and I began writing the campaign around setpiece locations. The party recruited allies for a big battle that would have taken months of travel before, and they could always return to base in the blink of an eye.

I loved every minute of it!
2/2

— Justice Arman 📜 Candlekeep 🏰📚 (@justice_arman) April 21, 2020

Totally. That whole 13~16th is a bit of a blur. Our party got really good at escaping with Word of Recall until the bad guy painted his house with gorgon's blood 🤣

— Justice Arman 📜 Candlekeep 🏰📚 (@justice_arman) April 21, 2020

What does wyvern or dragon meat taste like? I’ve tried alligator meat before, but I don’t know if it would be a similar taste or not.

— Leslie Courtney (@LeslieCourtne14) March 28, 2020

1)
My relatively limited experience of wyvern- and dragon-meat cuisine has led me to depend on Elminster, Laeral, Storm, and (wince) Volo as sources. They all tell me the taste varies with age, species, and diet of what’s being…#Realmslore https://twitter.com/LeslieCourtne14/status/1244018258627493889 … 2)
…eaten, even before sauces and seasonings during cooking enter the picture. Raw meat tends to taste like frogs (as in, frog legs from a buffet) with a smoky aftertaste, and when cooked shifts towards the fine white meat part…#Realmslore

— Ed Greenwood (@TheEdVerse) March 29, 2020

3)
…of a well-done pork chop. With a smoky aftertaste.#Realmslore

— Ed Greenwood (@TheEdVerse) March 29, 2020

I am prepping a campaign set in your classic gray box edition of the Forgotten Realms. Did you consider Half Orcs a playable race at the table? I know they were included in the AD&D 1e PHB but could not find much about them in the Cyclopedia booklet. Yes, I do. Jeff and Karen had to "cram" that boxed set; it could only hold a 30th of what I sent them. Many things had to be omitted or dealt with in a handful of words.
Key to a half-orc character: how do they see themselves as fitting in, given their childhood?#Realmslore

— Ed Greenwood (@TheEdVerse) May 29, 2020