The Solgaleo & Lunala GX (254 / 236) card can be found in the Cosmic Eclipse set.
Recently sold 5 times and based on those sales is worth around £36.23.
Currently, there are 7 open listings for this card on ebay.
This card sells in the range of £27.30 to £45.16, making it quite stable.
This Rare Rainbow card was illustrated by Hideki Ishikawa.