Is there a way to aggregate frequency distribution for many runs?
My question is is there a way to aggregate all the frequency distributions for all the fitness values among the 30 runs? so that I can only show a single plot for all the runs.


Yes absolutely, you can do that with boxplots or violin plots, one boxplot (or violin plot) for each fitness value. The height and shape shows the distribution of the values across runs for one fitness value, and allows visual comparison between the different fitness values.