A big thing I've found in fantasy games is that a lot of people want to play evil races. Back in 2e, it was drow. Came 3e (then 3.5 & PF) this tendency has changed someone to some "less offensive races." 4e gave us tieflings as a core race. Still goblins, kobolds, and orcs find their ways into our games.
Yet few games allow them to be as cool as their parent race. Instead they become pussified versions of the race. Such as a whiny little dual-scimitar wielding ranger with his cat. Or they become just "humans with different abilities". Unfortunately the background for some of these creatures is such that to include them in a regular game without creating unbalanced situations... Like when the party discovers they have a drow among them.
I remember back in 2007 when Wizards announced that kobolds would become a player race. It created a lot of turmoil. Not only were kobolds well-established villains across Greyhawk, we had a big storyline that put them as villains for the County, but they were a mortal enemy to one of the major PC race (gnomes). That really annoyed me at the time.
During my tenure as a Venture Captain, I maintained the experience of LG. Do not allow evil races or races who are natural enemies of core races. To their credit, leadership listened and provided great player options through boons and later open play. The races they allowed, though I have issue with their power level (Aasimar and tiefling), but they were nevertheless neither direct opponents of a core race so they worked.
SO why am I thinking of this?
Because I am planning on using such a race in Legacies. Think about which such race you would like to see? Is there one race that could be added to the campaign?