The Python tool! I attended a session at Inspire 2019 that opened my eyes to all of the possibilities of Alteryx + Python... You can extend Alteryx to do pretty much whatever you want - if there isn't an Alteryx tool for it (yet), there's probably a Python library for it!
Plus, you can use the familiar drag-and-drop interface to do your file i/o and data prep, and then use Python to do the rest. An example is complex charts that aren't available in the Interactive Chart tool, or specialty operations. For example, we used Alteryx to generate an animated gif by using Alteryx tools to generate the individual frames, and then the Python tool to assemble them together and output the gif).