most popular john deere tractor ever
Ford N series, tho that is the 9N, 2N, and 8N all wrapped together. The John Deere 4020 is still one of the most popular tractors ever, enough power to still be useful, very fuel efficient, and has nice features. Those Farmall H's and M's were real popular too, made for a long time, good cheap power back in the day. Allis Chalmers WD was probably their front runner.