Solar trackers are devices that rotate your solar panels to ensure that they’re facing the sun as much as possible. These range from passive, single-axis trackers, to dual-axis trackers with a motor that ensures they’re always in the optimal position.  Solar trackers can increase the cost of your solar panel installation, but they can also reduce the number of panels you need.
Whether or not solar trackers are worth it depends on how much additional sunlight they would capture throughout the year.