Hey guys,
I was looking at the list of blastoise cards that @quuador made(thanks again) and I have found that for the expedition set there are 2 blastoise cards that are the same but have different numbers, my question is simple…why? Are they different?
(I am trying to do my own list with the cards that I would like to have)
The 2 blastoise are the number 4/165 and the 37/165.
One is holo and the other is non holo
4/165 is holo and ist 37/165 non holo or reverse holo
Small correction: 4/165 is Holofoil or Reverse Holo and 37/165 is non-Holo or Reverse Holo. 
To quote Bulbapedia:
Both Reverse Holo variations are available.
A more generation answer however: in some WotC sets (like Jungle, Fossil, Expedition Base Set, Aquapolis, etc.) the same card artwork for Holofoil and non-Holo usually had different set numbers. In the Jungle set you for example have Holofoil Rares from 1/64 to and including 16/64, and after that the exact same cards but as non-Holo Rare for the numbers 17/64 to and including 32/64.
This Blastoise from the Expedition Base Set is similar.
Greetz,
Quuador
#4 is always reverse or regular holo, number 37 is always non holo or reverse. The other blastoise art is #36 and is either reverse foil or non holo.
Well…that’s why I couldn’t find the 37/165 holo in the last 45 minutes… I was thinking about this reason, but you confirmed this😅.
Thanks guys! 
The #36 is just non holo and reverse then?
You saved me from another headache 
That is correct!
To add to this point- you can distinguish the reverse holo’s from each other by looking not only @ the set number, but the “E” in the left corner also has variations.
#4 had a golden “E” when reverse (just like the holofoil version) while #36 & #37 have a ‘normal’ blue “E” in the corner (even when they are reverse)
Good luck in getting these beauty’s, they have awesome artwork IMO!
Thanks for the addition 