With the number of powerful opponents Goku has encountered, it’s really lucky that he hasn’t wound up dying more than he has. Even when facing Buu, someone who literally killed almost every single person on the Earth, Goku was still one of the lucky ones who didn’t get caught in the crossfire (even though he was already dead at the time, though that certainly didn’t effect his ability to get hurt in fights).
By Dragon Ball standards, Goku’s death count is on the low side at two. Not only that, but he’s been so fortunate in his fights that the only times he’s ever died were when he willingly sacrificed himself. The first was when he restrained his brother Raditz so Piccolo could finish him off with the Special Beam Cannon, a move that unfortunately necessitated Goku’s demise as well. And the second was when Cell was about to detonate himself to blow up the Earth, so Goku used his Instant Transmission to transport them both away. So in a way, the only person who has ever killed Goku is Goku.