Much like all Pokemon Games prior to this one, a player will still be able to receive a number of Gift Pokemon from other characters during their journey. However, unlike a lot of previous Pokemon Games, a player only has the chance of receiving five Gift Pokemon this Time around, one of which happens to be your Starter Pokemon.
Gift Pokemon
Starter Pokemon - Iki Town: After rescuing Lillie and Cosmog from the certain dangers of a flock vicious Spearow, you will ultimately meet Kahuna Hala and be given your Starter Pokemon by him. You have three options for you first Gift Pokemon (All at Level 5): Rowlet, Litten or Popplio. This will be the Pokemon you travel across The Alola Region with.
Eevee - Paniola Ranch: The first Time you ever visit the Pokemon Nursery in Paniola Ranch, you will be given an Egg by the owner of it. This Egg will later hatch into a Level Eevee, which you can later evolve into one of its eight Evolutions.
Porygon - Aether House: After defeating the Elite Four for the first Time, there will be an Aether Employee at Aether House that will give you a Level 30 Porygon as an apology for the actions of Foundation.
Aerodactyl - Seafolk Village: Once you arrive in Seafolk Village, there is a young trainer in Huntail Boat that will give you an Aerodactyl for nothing at all. It will be at Level 40.
Type: Null - Aether Paradise: After defeating the Elite Four, you can Return To Aether Paradise to find Gladion in the Conservation Area, actually in the exact place where you first met his mother. Still thankful for all of your assistance with saving his mother, he will give you the other Type: Null that The Aether Foundation created. Type: Null and its evolution Silvally were based on Arceus, and were created by the Aether Foundation to help Battle and capture Ultra Beasts. This is the only Type: Null, and ultimately way to obtain Silvally, in the entire game.