The Victini EX (131 / 135) card can be found in the Plasma Storm set.
Recently sold 4 times and based on those sales is worth around £12.22.
Currently, there are 9 open listings for this card on ebay.
This card sells in the range of £5.24 to £19.20, making it quite stable.
This Rare Ultra card was illustrated by Ryo Ueda.
The fact that it is a EX card makes it one of the more valuable cards.