The Factory Area covers the Depot Station, the Secret Warehouse and Reuniclus’s Laboratory. It is home to 39 Pokémon. Here is how to befriend them, based on the Poképédia list.

The Depot Station.
The Secret Warehouse.
The Laboratory.
No.PokémonHow to become friendsLocation
126GurdurrTalk to it after repairing the metal bridge (story)Depot Station
127ConkeldurrRepair the metal bridge (story)Depot Station
128GolettGive it a Music BoxDepot Station
129GolurkBeat it in a duel (story)Depot Station
130ZebstrikaBeat it in a raceDepot Station
131AccelgorBeat it in a race — available after repairing the metal bridgeDepot Station
132TyranitarBeat it in a duelDepot Station
133SalamenceBeat it in a duel — available after befriending MawileDepot Station
134MurkrowBeat it in a duelDepot Station
135HonchkrowBeat it in a duel — available after befriending MurkrowDepot Station
136AbraTalk to it after distracting it — available after repairing the metal bridgeDepot Station
137ScizorBeat it in a raceDepot Station
138EscavalierBeat it in a duel — available after befriending AccelgorDepot Station
139RoggenrolaBeat it in a duelDepot Station
140GigalithBeat it in a duel — available after befriending RoggenrolaDepot Station
141MawileGive it a jewel — available after repairing the metal bridgeDepot Station
142VoltorbAnswer its quiz correctly — available after repairing the metal bridgeDepot Station
143WynautFind it in a game of hide-and-seek — available after rescuing it from Wish ParkDepot Station
144KirliaOpen all the treasure chests in PokéPark — available after rescuing it from Wish ParkDepot Station
145LopunnyShow it a photo of Buneary — available after rescuing it from Wish ParkDepot Station
146EeveeComplete its course — available after befriending VoltorbDepot Station
147SolosisAnswer its quiz correctlyLaboratory
148DuosionShow it a photo of a sleeping MunnaLaboratory
149ReuniclusOpen the Black Ideals Orb with the help of Tornadus, Thundurus and Landorus (post-game)Laboratory
150SableyeFind it in a game of hide-and-seek — available after rescuing it from Wish ParkSecret Warehouse
151StunkyAnswer its quiz correctlySecret Warehouse
152JoltikAttack Garbodor to make Joltik fall, then talk to itSecret Warehouse and Lakeshore
153GalvantulaBeat it in a duel — available after befriending JoltikSecret Warehouse
154ElectivireBeat it in a duel — available after befriending GalvantulaSecret Warehouse
155GarbodorBeat it in a duelSecret Warehouse
156MagmortarBeat it in a duel — available after befriending ElectivireSecret Warehouse
157UmbreonComplete its course — available after rescuing it from Wish ParkSecret Warehouse
158SneaselBeat it in a duelSecret Warehouse
159GengarBeat it in a race — available after befriending SneaselSecret Warehouse
160DuskullBeat it in a duel in the hidden roomSecret Warehouse
161DusknoirBeat it in a duel — available after befriending DuskullSecret Warehouse
162KlinkFind Klang, Klinklang and it to repair the elevator (story)Secret Warehouse
163KlangFind Klink, Klinklang and it to repair the elevator (story)Secret Warehouse
164KlinklangFind Klink, Klang and it to repair the elevator (story)Secret Warehouse