Runes are magical abilities stored in Link's Sheika Slate. He gains these new abilities by completing the trials found in ancient shrines. They will be invaluable tools that will aid him on his adventure. In the E3 2016 demo, four of the Runes were showcased. It's currently unknown how many will be in the final game.
Create a pillar of ice from a water surface. Builds ice pillars that are very stable. These pillars can be used as stepping stones or as obstacles. Use Cryonis on an ice pillar to break it.
Manipulate metallic objects using magnetism. Grab on to metallic objects using the magnetic energy that pours forth from the Magnesis Rune. Objects held in the magnetic snare can be lifted up and moved freely.
Detonate the explosive using a remote trigger. The force of the blast can be used to damage monsters or destroy objects. There are both round and cube bombs, so use what would be the best fit for the situation.
Stop the flow of time for an object. Objects stopped in time will store kinetic energy. This stored energy will be expelled when the flow of time resumes. Making good use of the stored energy can move even the largest of objects. Take note of the time needed to recharge it.