1999–2004. A time of joy all around the world, but mainly Japan. This was a major release, with a serious anime (Chaotic Century/Guardian Force) to boot. Then, after a couple dozen reissues, new designs started appearing. Eventually the line just sort of petered out with little fanfare in 2004.
The “Side of Republic” Zoids.
In 2001 Zoids not only came back to the US, they also sometimes came with different colors.
In 2002 something weird happened. I think Tomy was courting the kid market… or something.