These cards typically had a brown and black artwork window, higher attack damage and lower HPs compared to normal Pokmon
You don't control any of that player's permanents, spells, or abilities
For one, it introduces Pokmon owned by characters other than the players of the game (for example, Brock's Rhydon #2 or Misty's Tentacruel #10), and it also shows Pokmon owned by non-Gym Leader characters (namely Team Rocket, as Rocket's Scyther #13 comes to mind here)
Taigam works wonders with an array of prowess creatures simply because youll be casting a lot of instants and sorceries in turn buffing your creatures along the way
Any Middle-earth big hitters that people want reprinted will likely show up on a bonus sheet or in an ancillary tie-in product like a Secret Lair, not in the main set - if they return at all
This isnt the deck with Seedborn Muse in it, but you could go that route anyway, making an 8/8 during everyones turn for no mana