Sometimes it's easy for your dog to get distracted in the yard, but if you'd rather have them keep their nose to the ground, hide a few treats while they're not looking (but make sure they're within reach!), then let them sniff around the yard to find them.
Yes, it is certainly simple, but if you have a yard big enough for it, fetch is still a great way to get your dog to burn some energy and stay entertained. If your yard isn't particularly long, try to work with height by using a Frisbee they have to leap for more than chase after or try bouncing a ball instead of tossing it so they try to catch it mid-air.
If you have a dog that needs to get rid of some energy but doesn't have a ton of space in the yard to run, get them running consistently instead of far. Grab a friend and your dog's favorite toy and toss it back and forth so they have to stay on the move to chase it. Make sure to let them get it occasionally or they may quickly lose interest.