I am reminded of the time where Ben Grimm managed to temporarily KO Immortal Hulk by landing a crazy full force haymaker. Such was the effort involved that Thing actually obliterated his own arm in the process.
Who could barely survive Thing's best hit? Who could survive his REGULAR hits but would DIE to his best self sacrificing blow?
Characters to consider would be like-
Regular Savage Hulk
Rhino
Thor
She-Hulk
Namor
Captain Britain
Thor, both classic and current
Nova
Anyone else?
The above are all 616 comics, below is MCU-
MCU Thanos and Cap Marvel