The Constructive Dialogue Institute's online "Perspectives" education program seems to have produced small to medium reductions in (self-rated) #polarization scores and increases in (self-rated) humility scores, including in longitudinal randomized controlled trials with government workers and students.
Submitted paper: https://constructivedialogue.org/articles/the-online-educational-program-perspectives-reduces-affective-polarization-and-increases-intellectual-humility
In press at Journal of Social and Political Psychology: https://doi.org/10.5964/jspp.10651
Materials: https://doi.org/10.23668/psycharchives.13036