The Dark Charizard (21 / 82) card can be found in the Team Rocket 1st Edition set.
Recently sold 7 times and based on those sales is worth around £58.00.
Currently, there are 41 open listings for this card on ebay.
This card sells in the range of £40.58 to £75.42, making it quite volatile.
This Rare card was illustrated by Ken Sugimori.