Junlong Zhang Last fight - 18.12.2017 Rostislav Plechko Last fight - 25.08.2018 Mladen Miljas Last fight - 09.08.2019 Tyrone Spong Last fight - 31.08.2019 Ruslan Myrsatayev Last fight - 26.10.2019 Tshibuabua Kalonga Last fight - 20.10.2018
Spong was supposed to fight Usyk after Takam pulled out but he failed a drugs test I think. Heard rumours of him fighting Dave Allen after that but nothing materialised.
Last i heard about Spong (boxing related) was he failed a drug test before a scheduled fight with Usyk, then Chazz Witherspoon stepped in. I don't know if he's gone back to other combat sports.
Zhang got in trouble with the Chinese government for not paying some sort of tax. He is banned from fighting but someone said that he is coming back (I have no idea if true). Sprong was covered above- PEDS. The others I imagine are just on the same covid stall as everyone.
Junlong Zhang was pretty much a Chinese Lovejoy with a padded record and almost no footage of his fights.
The last I heard Plechko dropped down to cruiserweight. He was a crude entertaining fighter who would have been destroyed by the first decent fighter he faced, he probably realised this himself.