Scientific Computing 2018 | College of the Atlantic

Software and Official Documentation

A matplotlib tutorial from DataCamp. This looks pretty good.
Pyplot tutorial. Looks like a reasonably friendly overview of some basic and slightly-less-than-basic plotting techniques.
Gallery of matplotlib examples. Includes a listing of markers and line styles.

Cheat Sheets from No Starch Press's Python Crash Course. These look excellent. There's even one specific to matplotlib.

Jesse M. Kinder and Philip Nelson, A Student's Guide to Python for Physical Modeling. Princeton University Press, 2015.
Allen Downey, Think Python (second edition). O'Reilly Media, 2015.
Charles Severance, Python for Everybody: Exploring Data in Python 3. CreateSpace Independent Publishing Platform, 2016.
John Zelle, Python Programming: an Introduction to Computer Science (third edition). Franklin, Beedle & Associate, 2016.
John V. Guttag, Introduction to Computation and Programming Using Python: With Application to Understanding Data (second edition). MIT Press, 2016.
Kieran Healy, Data Visualization for Social Science A practical introduction with R and ggplot2, Princeton University Press, forthcoming. This is not about python, but nevertheless looks like a very useful resource. It appears that a complete draft of the book is onlin in an easy-to-read format.