Unlike separate Pokémon game versions such as Sword & Shield, The Isle of Armor DLC does not have a large amount of exclusive Pokémon based on the player’s base game. There are several different species which are only found if you’re playing in Pokémon Sword or Pokémon Shield, however, and you can find them listed below.
Pokémon Exclusive to DLC Played on Sword
No. 127: Pinsir

Found in: Training Lowlands, Max Raid Battles
No. 539: Sawk

Found in: Max Raid Battles
No. 692: Clauncher

Found in: Workout Sea, Stepping-Stone Sea, Insular Sea, Honeycalm Sea, Honeycalm Island and Max Raid Battles
No. 693: Clawitzer

Found in: Workout Sea, Stepping-Stone Sea, Insular Sea, Honeycalm Sea, Honeycalm Island and Max Raid Battles
Pokémon Exclusive to DLC Played on Shield
No. 214: Heracross

Found in: Training Lowlands, Max Raid Battles
No. 538: Throh

Found in: Max Raid Battles
No. 690: Skrelp

Found in: Workout Sea, Stepping-Stone Sea, Insular Sea, Honeycalm Sea, Honeycalm Island and Max Raid Battles
No. 691: Dragalge

Found in: Workout Sea, Stepping-Stone Sea, Insular Sea, Honeycalm Sea, Honeycalm Island and Max Raid Battles