Here is what Sprout Valley: Friends Forever expansion has to offer all farmers:

• 11 new friends that can be found while visiting new islands. Each of them has their own gift preferences, hobbies, unique style, and they’re all different kids of creatures - from buffalos to frogs!
  
• Each new islands dweller has a questline, at the end of which await new workspaces, items, and rewards.
  
• New boat colors and decorations to unlock.
  
• And new looks for containers like Nico’s chest, backpack, the mailbox, etc!