Mean of max's? no problem
import arcpy
arcpy.env.workspace = r"C:\Data\rasters"
import numpy as np
r_max_mean = []
for raster in arcpy.ListRasters("*"):
ras = arcpy.RasterToNumPyArray(raster)
r_max_mean.append( np.nanmax(ras) )
print("max_list\n{}\nmean_max {}".format(r_max_mean, np.nanmean(r_max_mean)))
max_list
[255, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99]
mean_max 103.875