With isocalc, isotopic patterns can be calculated from python. It is not accurate (e.g. not considering electrons), and very inefficient, but still sometimes useful for quickly screening isotopic patterns and for teaching. For example, the code

from isocalc import isocalc
isocalc.plot_isotope_distribution("C1")

will result in the following plot:

While the following code:

from isocalc import isocalc
isocalc.plot_isotope_distribution("C1Br4")

will result in the following plot with several isotopic peaks: