I know I keep including more than 1 card but, these two are intertwined for me as well. Both pulls from when I was a kid, both from the same set, and both cards I decided to keep when I sold the majority of my childhood collection a few years back.
(Base Set 
I was going to choose my signature card and then went with this. One of my favorite Gyarados cards that has my favorite water Pokemon in Cameo
Has to be the OG Arita Squirtle. When I think of my first starter, this image is bubbled into my brain.
I was going to choose an Azumarill card, but then remembered I got this cute Marill sundae gachapon in Japan, so I pulled out my signed Marill card to pair with it. 
The first Pokémon of Red in the manga, Satoshi Tajiri’s favorite Pokémon, and it has a very beautiful card with a Poké Ball pattern.
Poliwhirl/Nyorozo — Scarlet & Violet era, 151 expansion.
058/L-P : Lapras.
Really love this Lapras challenge Plaza promo. Super awesome depiction of the Pokemon and also one of the very few promos that exist for Lapras.
Cheers!
Wartortle 019/029 
(Pokémon e-Starter Deck ) [1st Edition] (2001)
Honestly I love this illustration so much!!! It’s awesome!!!
Alakazam - Masaki Evolution Campaign.
The best part about having this card in my collection that this was an actual trade with a fellow E4 member. So pretty special card for me. Atleast it symbolized a level of trust and friendship you can have with fellow collectors on the forum to be able to trade for cards like these.
Cheers!
Since @niece already posted the Alakazam I planned on posting above, I’ll go with the Japanese Radiant one instead. The reflections in the sunlight really suits the card, with its spoons and white sparks in the artwork background imo. 
(I’m surprised to see this is just a ~4 USD card on eBay rn. 
)
Greetz,
Quuador
