A brush hog is the best metal detector for farm fencing and logging cable that has ever been invented.
🦫
LOL...
Yeah, I could write a book.
Most of the time it's old, rolled up barbwire, and sometimes cattle panels left flat on the ground.
But once, I found an old steel/porcelain bath tub they'd used as a water trough, but had been dragged off and weeds/brush had grown up so that I couldn't see it.
Hit the PTO kill switch quick, but not before it looked like a rolled up burrito.