I have a bunch of plots as the one reported below. The data is from measurements performed on different times and different days.
In the plot (which is a cumulative distribution function, if that matters), the colors differentiate data relevant to different days; the markers are used to further differentiate the data within each day. 
The problem is that the plot is very crowded and a bit ugly. Some markers can be barely seen.

**Question: Any idea how I can better plot this data?**

As you can see I tried to scatter the markers so that they would not appear in the same position.
The code I used to create the markers (with python/matplotlib): 

    marker_list = ['$A$', '$B$', '$C$', '$D$', '$E$', '$F$', '$G$', '$H$', '$I$', '$J$',
                   '$K$', '$L$', '$M$', '$N$', '$O$', '$P$', '$Q$', '$R$', '$S$', '$T$',
                   '$U$', '$V$', '$W$', '$X$', '$Y$', '$Z$', r'$\Gamma$', r'$\Lambda$', 
                   r'$\Omega$', r'$\Psi$',]
       
    'set marker position'
    rnd_lst = [np.random.randint(-10, 10) for i, _ in enumerate(marker_list)]
    marker_pos = [[25+x, 45+x, 65+x, 87+x] for x in rnd_lst]    # fixed points + random number to scatter the markers

    cc = plt.cycler(marker=marker_list, markevery=marker_pos)
    plt.rc('axes', prop_cycle=cc)
    plt.rc('lines', markersize=18)


However, it would be nice to "distribute the markers in the y direction". For example, it'd be nice to show the markers only where the CDF is above 0.25. 

**Question: how to limit the markers to a specific section of the y axis?**

[![Cumulative distribution function][1]][1]


  [1]: https://i.sstatic.net/C1bXU.png