R Packages book by Hadley Wickham and Jenny Bryan.
Forwards workshops on package development – notes taken by Stefanie Butland.
R-hub blog e.g. Checking the inputs of your R functions & Coding style, coding etiquette.
Writing R Extensions (one piece at a time).
Advanced R by Hadley Wickham.
My own blog post with many links to fantastic resources: “How to develop good R packages”.
A Beginner’s Guide to Travis-CI for R by Julia Silge (for learning about continuous integration; Travis itself is no longer recommended).
GitHub Actions for R by Jim Hester.
prefixer package, “Prefix function with their namespace”.