The Solgaleo & Lunala GX (254 / 236) card can be found in the Cosmic Eclipse set.
Recently sold 16 times and based on those sales is worth around £27.70.
Currently, there are 7 open listings for this card on ebay.
This card sells in the range of £13.46 to £41.94, making it quite volatile.
This Rare Rainbow card was illustrated by Hideki Ishikawa.