I missed the golden era, but recently I’ve become kind of obsessed with it. I’ll share what I’ve enjoyed so far.
If you want to see where kickboxing came from and its evolution, I would suggest you start with some of the legends from the 60s-80s. Guys like Tadashi Sawamura, Benny Urquidez, Joe Lewis, Don Wilson, Bill Wallace, Rick Roufus, Jean Yves Thériault, Rob Kaman, Ramon Dekkers.
K-1 is the golden age and produced so many legends worth checking out: Ernesto Hoost, Peter Aerts, Semmy Schilt, Mike Bernardo, Jarome LeBanner, Remmy Bonjansky, Badr Hari, Mirko Crocop, Andy Hug, Buakaw, Masato, Mike Zambidis, John Wayne Parr, Andy Souwer. I think all of those guys are worth checking out, and I know I’m missing more.
I became interested in kickboxing when Glory was making a push in America and from that era I would recommend Giorgio Peteosyan (goat), Nicky Holzken, Fang Bian, Artem Levin, Simon Marcus, Robin Van Roosmalen, Sittichai, Yodsanklai, Rico Verhoeven, Gokhan Saki, Tyrone Spong, Joseph Valtellini.
Also, check out the careers of top guys that have left for boxing or mma, like Tenshin, Alex Periera, Cedric Doumbe, and Tyjani Beztati. Cung Le also had some great fights before committing to mma.
My current favourites are Bahram Rajabzadeh, Artem Vakhitov, Petch, Superbon, Chingiz Allazov (don’t know what’s going on with him?), Superlek, Tawanchai, Rodtang, Takeru, Marat Grigorian, Miguel Trindade, Yuki Yoza, Nabil Anane, Jonas Salsicha, and Elias Ennahachi.
I’d also suggest you check out Saenchai, if you haven’t already. He’s a Muay Thai guy, and an absolute legend.
I’ve found BeyondKick is a good source for following the sport.