The Cliff´s Delta Calculator (CDC) provies effect sizes for the comparison between two vectors of observations. These vectors do not require normality assumption. Hence, the CDC can be applied to analyze non-parametric distributions. The CDC software can be downloaded from here, and the corresponding paper is available in this link.
The absolute value of the Cliff´s Delta can be considered small around 0.147, medium around 0.33, and large around 0.474.