Depends upon the definition of “greatest.”
From a branding and recall standpoint, it would have to be Gravedigger. I’ve never been to a monster truck event and only vaguely understand the appeal of it. But, I could tell you almost exactly what it looks like.
Bigfoot? No clue. The images here appear to be fairly run of the mill Ford muddin’ truck.
I’m pretty sure who’s making the most money on collectibles and fanwear as a result. Whether that translates at the gate, I couldn’t say but it should.