This is where I'm getting Eladrin for FR, I know they got a make over in 5e but since they were introduced in 4e I'm presuming they are still their. Now, warforged and changelings as far as I know didn't make it over, but I don't have 5e stuff or read any books.
Seeing a changeling race though, that would be pretty epic, probably more than seeing a donkey.
Eladrin race block was published in Mordenkainen's Tome of Foes, as a subrace of Elf, so they are a little rarer, but they are absolutely a thing for 5e, and because the Tief subraces that BG3 uses also come from Mordy's, clearly someone at larian knows that book exists, so hopefully we'll get Eladrin too.
Warforged and Changelings have both been redone for 5e and were published in Eberron: Rising From the Last War (although personally i prefer the unearthed arcana version of warforged). It's important to note that because they were published for Eberron doesn't mean that they are also in the Forgotten Realms, BUT far too many people I know (myself included) like to casually cross over Eberron and FR all the time.
I have a feeling that they won't show up in BG3 unless someone mods it in though.
