The Mewtwo (11 / 146) card can be found in the Legends Awakened set.
Recently sold 8 times and based on those sales is worth around £12.44.
Currently, there are 11 open listings for this card on ebay.
This card sells in the range of £6.30 to £18.58, making it quite stable.
This Rare Holo card was illustrated by Ken Sugimori.