Here is the full list of all 15 Disney Infinity 3.0: Play Without Limits achievements.
Save a Toy Box
Throw a party for your friends in one of the designated Sidekick Rooms
Reveal all the terrain in the Toy Box Hub
Play all Toy Box Adventures
Complete 75 Feats
Feed Sidekick 50 times
Harvest 100 plants
Complete 50 Feats
Build a 20-room INterior
Earn 10 Toy Presents in the Toy Box Hub
Play a downloaded UGC in the theater (Steam, Single Player Only)
Complete 25 Feats
Earn 5 Sidekicks
Complete 5 Feats
Complete all Toy Box and INterior tutorials