hard establish a top 5 kickboxers all time,because there are too much epic guys.
Legendary before K1 days:Rob Kaman,Changpuek Kiatsongrit,Ramon Dekkers(from muay thai too),Peter Hurricane Smith.
K-1 Heavyweight time: Peter Aerts,Ernesto Hoost,Andy Hug,Jerome Le Banner,Remy Bonjasky,Semmy Schilt,Alexey Ignashov,Stefan Leko,Mike Bernardo,Ray Sefo,Glaube Feitosa,Sam Grego,Cro crop,Badr Hari and Overeem(2008-2010 days).
K-1 Max time:Buakaw,Andy Souwer,Masato,Albert Kraus,Giorgio Petrosyan,Artur Kyshenko,Yoshihiro Sato,Mike Zambidis,Gago Drago.
Nowdays:
Heavyweight Division:Badr Hari,Daniel Ghita,Rico Verhoeven,Adegbuyi,Anderson Silva,Zimmerman.
Light Heavyweight:Gohkan Saki,Tyrone Spong,Zabit Samedov,Danyo Ilunga,Saulo Cavalari,Artem Vakhitov.
Middleweight:Artem Levin,Simon Marcus,Joe Schilling,Fang Bian,Jason Wilnys,Alex Pereira.
Welterweight:Nieky Hozken,Artur Kyshenko,Joseph Valtelini,Murthel Groenhart,Aleksandr Steturenko,Raymond Daniels
Lightweight Division:Giorgio Petrosyan,Robin Van Roosmalen,Davit Kiria,Andy Ristie,Mohamed Khamal,Sitthichai Sitsongpeenong,Marat Grigorian,Enriko Kehl,Yodsanklai Fairtex(need more fights in kickboxing,he is contracted on K1 now).
Featherweight:Kaew Fairtex,Mosab Amrani,Gabriel Varga,Yuta Kubo,Soda,Jomthong,Masaaki Noiri,Massaro Glunder(new guy for us,showed a supernatural talent and fight style).
55kg:Takeru,Taiga.