I would have to say that my favorite "round" for coyotes is the rounded edge of my trucks front bumper.
Remington makes a sabot round for the .30-06 called the accelerator. 60 grain BT HP .223 saboted into a .30-06 case. I used to use my .270 with 110 grain target loads before I sold my .270. Both were highly effective out to 300 yards.
My personal preference isn't even a bullet (or a truck part!). I prefer to use my Parker Buck Hunter compound bow, set at 55#, with Carbon Express Terminator carbon fiber arrows, cut to 27.5 inches with a 60\70 spine. Tipped with, 100 grain G2 ripper tri-blade broadheads. Properly placed, this set up is fatal out to 60 yards, and is quiet enough to not spook any other 'yotes out of coming into range.