There are several examples from icy and rocky worlds in our Solar System explored by spacecraft of volcanic processes either occurring or having occurred in the past. Volcanism is apparently a common process and displays a wide variety of forms. We have yet to explore, however, metal worlds (i.e., the exposed cores of differentiated planetesimals).
Abrahams and Nimmo  seek to determine whether ancient metallic volcanism could have happened on a metal asteroid. Unfortunately, observations of metal asteroids are largely just points of light in the sky, tantalizingly unresolved. The authors thus make predictions that may enable exploration via variations seen in iron meteorites. In addition, this possibly sets the stage for potentially amazing discoveries when Psyche (the spacecraft) arrives at Psyche (the asteroid), as no one knows the form that metal volcanic constructs could take.
Citation: Abrahams, J. N. H., & Nimmo, F. . Ferrovolcanism: Iron volcanism on metallic asteroids. Geophysical Research Letters, 46. https://doi.org/10.1029/2019GL082542
—Andrew Dombard, Editor, Geophysical Research Letters