Many. A tavern in my worlds will often look like the cantina from Star Wars.Lots of talking about playable character races in the last year or two... what are your preferences regarding the following approaches? (You can specify whether you are answering from a player's or DM's point of view)
1) Few or plenty?
Variable. In fact in my 13th age game I've removed stat bonuses from races and put them onto classes and have tweaked the racial abilities so the players can pick from a few different ones based on the theme around the race rather than being locked into a single choice. NPC members of individual races will have characteristics suitable to their roles. For 5e I would prefer more variety over less.2) Common or variable?
Outsiders are fine within reason. I'm not big on people bringing characters from other campaigns into my game, but a character that starts in my game but is from another plane or world is fine as long as we talk about expectations for why the player wants that kind of character.3) Native or outsiders?
Allow, and the narrative would be whatever I and the player come up with in collaboration.Bonus question (kind of a combination of questions 2 and 3): how do you feel about using different versions of a race from different settings? Examples could be allowing Zendikar elves or Ravnica goblins (assuming you already have native elves or goblins), would you be ok with allowing the mechanical variant (i.e. different stats and abilities) from another setting? If you would allow the mechanic, would you disallow, allow or even require the narrative that the race comes from another world?
Basically my attitude is always "bring me your idea and we'll tweak it to make it work" when it comes to PCs. But also my players don't try to break the campaign that we're playing in - once we decide on the campaign we're playing players come up with ideas for that campaign and I've never really had a problem with a player trying to push something that we couldn't make fit.