The Slowpoke (66 / 90) card can be found in the Hs Undaunted set.
Recently sold 2 times and based on those sales is worth around £2.35.
Currently, there are 7 open listings for this card on ebay.
This card sells in the range of £2.10 to £2.60, making it very stable.
This Common card was illustrated by Kagemaru Himeno.