Some stuff I've grown to like during my PhD and think others might also be interested in. No holy grail, just things I find useful.
Paul Goldsmith-Pinkham Beamer slides --> seriously, you have to love this template. And it comes with good advice on how to present too.
Blindschemes for Stata --> Easy makeover for those light blue background plots, without wasting a lot of time. Look for “New Graphic Schemes for Stata: plotplain & plottig”.
Publication quality plots with Matlab --> Don't be lazy and stop using those default Matlab graphs.
Colorblind friendly graphs --> Because some people can't distinguish that red line from that green line in your graph.
Asana --> Because that to-do list on post-its around my desk was getting hard to track.
Self-control --> Because some times you need to "tie yourself to the mast", suggested by @Abdounomics
Be Focused --> App to time and keep track of extremely focused moments of work, "pomodoros", and take breaks from them.
10 tips for PhD students and 10 tips for advisors, by Jon Levy
So you'll be in the (econ) job market next fall: 4 avoidable mistakes and 7 things to do to avoid them, by me (based on Matthias Doepke's advice).
If you like working with music, here are some of my favorite playlists: