First off, don't continue to read this if you wish to be surprised by the Pokémon Sword and Pokémon Shield expansion pass. With that being said, let me begin.

As you already know the DLC will contain forms of Pokémon that already existed. Some of these are :
- Galarian Slowbro (Psychic/Poison)
- Galarian Slowking (Psychic/Dark)
- Galarian Articuno (Ice/Ghost)
- Galarian Zapdos (Electric/Fighting)
- Galarian Moltres (Fire/Dark)
- Regielectric (Electric)
- Regidragon (Dragon)
- Galarian Shuppet/ Banette (Ghost/Grass)
-Galarian Gliscor (Dark/Flying)
- Galarian Ducklett (Water/Flying)
-Galarian Swanna (Dark/Flying)
- Galarian Tropius (Grass)
- Galarian Stantler (Ice)
- Galarian Buizel/Floatzel (Grass/Ice)
- Galarian Buneary (Ghost)
- Galarian Lopunny (Ghost/Dark)
- Galarian Seel/Dewgong (Water/Fairy)
- Galarian Chatot (Flying/Grass)
-Galarian Lilligant (Grass/Fairy)
- Galarian Lillipup/Herdier/Stoutland (Fighting)

Of course there are more regional evolutions as well :
- Troputrard (Grass/Poison) (Galarian Tropius evolution)
- Guilloking (Dark/Steel) (Male Bisharp evolution)
- Guillaqueen (Dark/Steel) (Female Bisharp evolution)
- Antarrein (Ice) (Galarian Stantler evolution)
- Mucarnivose (Grass/Poison) (Carnivine evolution)
-Quieatus (Dark/Fairy) (Hypno evolution)
- Narcaptice (Dark/Fairy) (Zorua alt. evolution)

And the new Regis :
- Regielectric (Electric)
- Regidragon (Dragon)

Some New Pokémon:
- Plunglet>Scubigle (Water/Flying)
- Loburrow (Water/Ground)
- Calfur>Coawtle (Normal)
- Pigrowth>Rootusk (Grass/Ground)

Some more old Pokémon coming to the game include :
- Unova Starters
- Galvantula line
- Ursaring line
- Raticate line
- Johto Starters
- Sinnoh Starters
- Eelektross line
- Ampharos line

Sorry to end this off but I'm only allowed 2000 words so goodbye for now, I might come back but I'm not sure, I'm risking my job and with the virus still going around I'd like to keep it.