For World’s each year Pokémon publishes the deck lists of all the winners and runner-ups.
However it is much harder to find deck lists from Japanese tournament winners from 1997-2003 (regional battles). There are occasional old blog posts where people mention the decks they used. I have found a few full deck lists but it is not easy. Has anyone compiled a list of decks used in the earliest tournaments? I thought it would be cool to see.
Idk if you have already seen this but there are a lot of lists here:
jklaczpokemon.wordpress.com/1999-base-jungle/
This book has some similar lists (and the book cover is holographic lol):
Pokemon Trading Card Game Fossil Expansion Player’s Guide
by Brian Brokaw and J. Douglas Arnold
The lists all look pretty similar with a lot of energy removal, bills, oaks, item finders, and computer searches.
This site has results/lists from the earliest WOTC events in US/EU if it helps 
Japanese tournaments seem a lot harder to find…
Japanese tournaments had a higher number of banned cards, most notably limiting Super Energy Removal to only one copy per deck, and some . I’ve recently gotten into building vintage decks and yeah, the website @w7west linked is probably the best you’re going to get, it was written by the winner of the 2006, 2008, and the 2013 World Championships. Pojo also has a list of decks used in tournaments if you want a broader overview of what kind of decks were being played. Generally speaking, Haymaker was most dominant during Base-Fossil alongside Raindance decks and some stall decks. Feel free to message me about anything if you want to discuss
Try digging around Pojo.com and Archive.org.
WARNING: Pojo can eat up a BUNCH of time. So much nostalgia!
Thanks all! I love these links resources and use them myself. I’m mostly curious though if the meta in Japan was similar to in US and if the same decks (Haymarker, Raindance etc) were used.