Pikachu happens to be one of the poster-children of Pokemon so it definitely has more prints than a lot of cards, but even if you imagine 10% of that as an average per Pokemon (14 variations, or 5.5 prints) and multiply that out by the number of Pokemon presently in the franchise (721) youre looking at ~10k cards with variations or ~4k unique prints
1 Avacyn, Angel of Hope The ender of games
Trading Card Game has changed drastically over the years
Bandai still holds the events periodically, but the Zoro card was only distributed during that time period and has rotated the prizes since then
Legality depends on the tournament format -- Spell Purification can be legal in some formats and banned or restricted in others
Be fun to play with, be a great loser, and congratulate everyone on what they do, because most players put a lot of time into their decks and it feels good to be told that something they did was awesome