The Celebi (145 / 144) card can be found in the Skyridge set.
Recently sold 5 times and based on those sales is worth around £506.28.
Currently, there are 2 open listings for this card on ebay.
This card sells in the range of £112.67 to £899.89, making it highly volatile.
This Rare Secret card was illustrated by Mitsuhiro Arita.