Thing is pretty tough and has lots of muscles. Of course Venom is faster and more agile. He also has powers beyond Thing’s comprehension. Thing has fire and stretching powers, but that’s not enough. Venom wins.
Bizarro is just like Superman, except he talks backwards. The big difference is that Bizarro is slightly stronger physically than Superman. I’m not even sure what his origin is. He’s just super strong and if he can beat Superman he can beat a lot of people. The Thing however is a lot less impressive. He can barely beat Spiderman much less Bizarro. Bizarro wins.
The Thing is slightly powerful but he doesn’t have the smarts to use it right. Instead he’s rotting in the Fantastic Four. Manthing on rhe other hand is saving the world from utter destruction. Manthing has always been extremely powerful but now he’s even stronger than usual. The Thing will never be in his league. Manthing wins.