I started as a 7 y.o. kid back in 1999, until I was around 14-15.
I started collecting again mid/late-2015 (when I was 23 years old). At the time I was mostly collecting Yu-Gi-Oh, but on impulse decided to put all Pikachu TCG cards that were in stock on TrollAndToad for <50 USD each in my cart, and that was basically the start of my Pikachu collection. 
I mostly did so, because I thought collecting all Pikachu cards would keep me busy for a while, which was an understatement, haha. 
TCG:
- Pikachu TCG cards in all languages and variations up to Feb. 27th, 2021 (25th Pokémon Day), as well as ALL English Pikachu TCG; the Base Set artwork reprints in all languages; and one of each non-English exclusive artwork, after that date. Right now, my English Pikachu TCG collection is 100% complete, and I’m missing just five Japanese; two German; and two Spanish cards from before 2021. (Pictures of my Pikachu collection can be found in the links in the main post of my collection thread.)
- All English full art Supporter and Character Rare cards, as well as non-English exclusive artworks. Apart from incoming new releases, collection is 100% complete. (Slightly outdated scans/pictures can be found here.)
- All Seviper TCG cards in all languages. Apart from incoming new releases, this collection is also 100% complete. (Seviper is my favorite Pokémon.) (Pictures can be found here.)
- The Moltres WotC #21 promo in all languages; raw, sealed, and graded. The raw collection is complete; the sealed collection I’m not sure - I feel like the Danish one should exist because I’ve seen the Ancient Mew, but I’ve never seen any Legendary Birds with this insert yet; the graded collection is missing the Italian, German, Australian, and UK grading companies. (This artwork is my favorite of the entire Pokémon TCG.) (Pictures can be found here.)
- The BREAKthrough Swablu in all languages. This collection is also 100% complete. (This artwork is my second favorite artwork of the entire Pokémon TCG.) (A picture can be found here.)
- The first TCG card released in every language. Currently missing the new Latin American Spanish Caterpie. (A picture can be found here.)
- Ancient Mew sixtet in PSA-10. (A picture can be found here.)
Non-TCG:
- I collection anything and everything for Seviper. Non-TCG cards; stickers; pogs; posters; DVDs; plushies; figures; etc. etc. (My non-TCG Seviper collection can be found here, although I’ve added new items since then and also have a lot more incoming.)
- I’ve got a complete Bandai Carddass collection. (Pictures can be found within the spoiler tag here.)
- I’ve got a complete English TFG collection. (A picture can be found here.) The Italian TFG set is also complete, and I’m still trying to find three German and four French TFG cards to fully complete it in all languages.
I’ve collected a lot in my life (post stamps; minerals, gemstones, and fossils; twisty puzzles; etc. etc.) But the only other ‘fandom’ I’ve collected are Yu-Gi-Oh cards. In the past, I mostly just bought cards to re-create online decks irl, even though I only had my little brother to duel with. These days however, I only try to keep up with all the Yu-Gi-Oh rarities, although it’s an almost inactive collection. And I buy cool error cards or the new LART carts every now and then. 
I’ve watched the entire anime; all episodes, movies, special/banned episodes, etc. I’ve never played the TCG nor any of the games, though.
I’m also a mod on this forum, and frequently visit it to read all new posts. I also visit the E4 Discord and some other Discord groups; some subreddits; and some IG Pokémon posts every now and then.
I’ve already mentioned my goals at the earlier question.
I’m mostly a completionist when it comes to my collection goals, aka “Gotta Catch 'Em All”. I also really enjoy learning more about the TCG, and I create posts or articles to help other collectors pretty often.
In general: it’s a hobby that keeps me busy. But in the almost ten years I’ve been collecting, I’ve felt a lot of different emotions on different occasions. Joy and relief when finally finding a card you’ve been looking for for 5+ years; stressed trying to keep up with 233 Pikachu TCG cards released in a single year (2019); conflicted when I was doubting about re-adjusting my collection goal from February 27th, 2021 onward; content with my decision, since it gave me the opportunity (and time/money) to focus on my other collection goals; surprise and utter euphoria when I sold three of my cards in order to buy a house (more on that in a bit); etc. etc.
I have Excel checklists for each of my collection goals: Pikachu; FA Supporters/CHRs; Seviper; Moltres; etc.
For my general Pokémon collection, I also have made a huge list of all the TCG cards I own (currently little over 15k unique cards).
After I sold my Japanese PSA-10 EBD trio in order to buy a house, the most expensive card in my collection right now is the Japanese PSA-10 The Masked Royal promo, which last time I checked is worth ~60-65k USD.
But apart from money, there are a few cards I would never sell no matter how much money someone would offer me (well, to some extend ), so I guess those are (for me personally) technically more valuable.
Definitely. I grew up with Pokémon, and it’s a huge aspect of my life. Some of my collection goals (like the Moltres) are due to that nostalgia, while others (like the FA Supporter/CHR) are more for the appreciation of the modern Pokémon artworks. I like all aspects and eras of the Pokémon TCG, and Pokémon in general. Even for the categories I’ve got little interest in myself, I still like that those aspects exist for others to enjoy (e.g. the games or playing the TCG).
Well, considering I bought three cards for roughly 4.5k USD, and was able to sell them just four years later for 150k USD, which enabled me to buy a house, despite being a single guy and this crazy housing market, I’d say it’s gotten pretty big. The literal fistfights at US supermarkets or the multi-million scam regarding the prototype cards is also a huge indication, and also clearly shows that there are also a lot of disadvantages in having an increasing monetary value overall..
Too many to name tbh. First episode me and my little brother saw (episode 2); first packs we’ve opened, and how I traded the holo Chansey pull away for a Vulpix, Pidgey, and Pidgeotto (as a kid I preferred quantity over quality); first Pokémon movie I saw in cinemas (the second movie, which is where I got the Moltres from); the crazy 150k sale mentioned earlier, so I could combine it with my savings money and mortgage to buy the house I currently live in; completing my Seviper TCG collection after ~4.5 years; going to Worlds in London and meeting fellow collectors I’ve previously only known online; being able to buy the final English Pikachu TCG card to complete that sub-collection after ~9 years; etc.
Relate to, not really. But Seviper is my favorite Pokémon. I’ve always been fascinated by snakes as a kid, and although some of the other snake Pokémon (Ekans, Arbok, Serperior, etc.) are also cool, Seviper’s design is just on a whole other level. It’s been my favorite Pokémon ever since I first saw it.
All the time. Although on this forum it’s usually more mellow and open-minded, with a few exceptions.
I basically grew up with Pokémon, and have also enjoyed collecting stuff, from 4-5 y.o. That, and this community, is what makes it special to me personally.
Not really. I don’t talk too much about Pokémon with family members; friends; or colleagues tbh. I guess one thing that a lot of outsiders have in common is saying things like “I’ve found my old childhood collection. Maybe it’s also worth thousands of USD.”, when in most cases they’re talking about heavy played unlimited edition English cards, and only care about the monetary value, instead of the nostalgia and memories that those old cards represent.
Greetz,
Quuador