Resources for Economics PhD students:
Steve Pischke (LSE) has a good collection of resources.
EconGrad advice curated by Chris Roth and @DSchindlerEcon
"Thriving in Economics" curated by @TDeryugina
Econometrics:
Development in Difference-in-Differences (DID), especially staggered DID:
Problems with two-way fixed-effects event-study regressions (by Brantly Callaway and Pedro H. C. Sant’Anna)
The Difference-in-Differences (R package)
Fortran:
List of optimization routines in Prof. Arnold Neumaier's website, including NLopt
Optimization software by late Professor M. J. D. Powell
Stata:
Stata for researchers, for students; very good introductions from SSCC@Wisc.
Data visualization: front-and-back plots (fabplot, subsetplot)
Latex/LyX:
Beamer: define a single background