Here's a compilation of what races are getting out of the recently released and delicious Advanced Race Guide. (:

Favored Class Options
Dwarves - Reduce the misfire chance for one type of firearm by 1/4. You cannot reduce the misfire chance of a firearm below 1.
Elves, Goblins - Add +1/3 on critical hit confirmation rolls made with firearms (maximum bonus of +5). This bonus does not stack with Critical Focus.
Gnomes - The gunslinger reduces the amount of time needed to restore a broken firearm using the Gunsmithing feat by 5 minutes (maximum reduction of 50 minutes).
Half-elves, Humans, Hobgoblin - Add +1/4 to the number of grit points in the gunslinger's grit pool.
Half-orcs - Add a +1/3 bonus on attack rolls when using the pistol whip deed.
Halflings - Add +1/4 to the doge bonus to AC granted by the nimble class feature (maximum +2) or +1/4 to the AC bonus gained when using the gunslinger's dodge deed.
Ifrit - Add +1/2 to the bonus on initiative checks the gunslinger makes while using her gunslinger initiative deed.
Kobold - Add +1/4 to the doge bonus to AC granted by the nimble class feature (maximum +4).
Ratfolks - Add a +1/2 bonus on initiative checks when the gunslinger has at least 1 grit point.
Grippli - Add a +1/4 bonus on attack rolls when making a utility shot or a dead shot.

Archetypes
Gnome - Experimental Gunsmith - Imbue your firearm with a number of alchemical and/or gadget options.
Human - Buccaneer - You're a pirate who can get bonus grit (kind of) by getting drunk. What more do you want? You even get a familiar/ship's pet.
Kobold - Bushwhacker - You specialize in ambushes and get your own version of sneak attack for firearms that stacks with regular sneak attack.
Ratfolk - Gulch gunner - Point-blank all out attacks with your firearm are your strength.