Both Voyagers are still collecting magnetic/plasma field and radiation data (only Voyager 1 is in interstellar space, Voyager 2 hasn't made it yet). Mostly they

Both Voyagers are still collecting magnetic/plasma field and radiation data (only Voyager 1 is in interstellar space, Voyager 2 hasn't made it yet). Mostly they are measuring the outer edges of the Sun's magnetosphere as it interacts with interstellar space, and it's a dynamic phenomenon so the data is actually more interesting than you might imagine. Several research papers a year continue to come out of the missions.