There are so many! Really surprised. Super interesting to see. I love connected cards.
I appreciate this is not exhaustive. But one my all time favourites are the Trainer B magazine Eeveelutions 
I couldn’t find them anywhere on my recent trip to Japan 
(Not my photo)
Always something to forget, i’ll include those the next time i’m taking photos 
I never noticed these artworks were connected, even though I’ve seen this picture of yours with them side-by-side a few times already. 
Greetz,
Quuador
Oh damn, wasn’t aware of the pidgey line and it’s gorgeous! That’s an easy add to my wants list, i love hgss/col era so i gladly take these kinds of opportunities to buy cards from them. Gyarados also is a beautiful pair and i have them in my wants list for another collection so will add them here too when i pull the trigger on them 
This side collection is becoming slightly dangerous since i’ve started to enjoy it a bit too much 
basically the only binder i’ve now gone through is the one with these connected cards in it now that i reorganized it during this photoshoot, i’ve gotten a sudden urge to collect stuff like T promos and the movie half decks since they have lots of connected art in them
You opened up a can of worms with this one. These are actually my favorite Suwama cards.
Call of Legends released a bunch of cards with alternative art from previously HGSS cards
(english only)
I think basically the whole set is like this
eg
Some new photos, both new additions and ones i’ve forgotten to include earlier, added them in op too
A nice catch! I like them so i’ll add them in my wants list
It’s indeed a beautiful one and i did actually pull feebas myself, unfortunately milotic is too pricy for me to complete the pair but i’m eagerly waiting how the simplified chinese price will look like when it gets released there
