--tooth bar for FEL to help dig with the FEL.
--box blade
--rear blade
--sacrifice teeth (normally comes with box blade, but some times comes with rear blades) generally required the teeth to break up hard pan (hard dry dirt on top as well)
--an off set rear blade (the blade swings off to either side further), might be nice.
--TNT (top and tilt) replace a top link on 3pt hitch with a hydraulic cylinder, and/or replacing at min 1 side link with a hydrualic cylinder. so you can adjust the 3pt hitch on the fly from seat of tractor.
--motor grader, (google it) the long distance between wheels. with blade / implement seating between the wheels. helps reduce high spots and low spots, that can be difficult to see from seat of tractor, until you get in a truck/car and start going 10 to 20MPH then you start feeling the ups and downs. there are DIY and bought pull behind graders out there as well.
--land plane / grader scraper, is more for rock, and sifting larger rock to the top and letting dirt and fines fall to the bottom. this is more of a maintenance attachment than building roads / maintaining dirt roads within reason.
google (forestry roads), there is a handful of descent sites that goes over various slopes, and like for both ditches, and crowns for roads.
with above said. for here on the farm. gravel drive way, to dirt roads, to grass lane through pasture. i have lots of hills and low spots and high spots. for me, having a rear blade or box blade or anything else run "level" with the tractor does me little good. i would need to adjust one of the 3pt hitch lift arm linkages. to angle it, to help maintain crown / slopes to help shed water. having an attachment that just barely covers tires. *meh* something a little bit wider would be nice. the time when a less width attachment would be better. is physically moving lots and lots of dirt and not just moving it a little bit here and there. but moving long distances. then a smaller width unit that you could fill up completely, might be better within reason. vs loosing your dirt little here and there due to attachment is to wide.
with above said. there is traction problem. and trying to take a bit of to much dirt at once. and bringing tractor to a stand still. either tires spinning, or just not enough umph to keep on going.
there other con's and pro's for each thing. box blade more for leveling and removing ruts. while other implements might be better wider? vs box blade? what do you plan to use for your total arsenal of attachments....