Complete PSA 10-graded sets of the Pokémon TCG Jungle and Fossil sets are currently up for auction.
I would like to postulate that the Japanese Quick Starter Gift Set released in 1998 contains the first examples of alt arts for the TCG, and that therefore they are the official
POKEMON COMPLETE 1st 3 SETS: BASE 102/102, JUNGLE 64/64 & FOSSIL 62/62 + BONUS
Fossil (TCG) - Bulbapedia, the community-driven Pokémon encyclopedia
The Pokemon Company
$3000 Entire lot of ungraded wotc base set unlimited. Yay or nay? : r/PokeInvesting
The Rarest and Most Expensive Pikachu Cards
Unbelievable rare Uncut Topps Chrome Sparkle Pokemon Sheet : r/PokemonTCG
Pallet Town Auctions
English Pokemon TCG
1999 Pokemon TCG Jungle 1st Edition Holographic #8 Pidgeot - BGS PRISTINE 10 - Pop 1 on Goldin Auctions