User's corner: ftools and gtools
Do you need to perform data management tasks or compute summary statistics with very large datasets? If so, and if you find yourself wishing you could do these things more quickly, you won't want to miss the solutions provided in the community-contributed ftools and gtools suites.
ftools, written by Sergio Correia, includes commands such as fcollapse for creating datasets of summary statistics, fmerge for merging datasets with one-to-one or many-to-one matching, and flevelsof for identifying distinct levels of a variable. The ftools suite also includes a Mata class for working with factors. The Stata commands in ftools are based on this Mata class. You can use it to implement your own commands too. ftools is available from the Statistical Software Components (SSC) archive, and you can read more about these commands in Sergio's slides from his presentation at the 2017 Stata Conference and his GitHub page.
gtools, by Mauricio Caceres, includes commands for quickly creating datasets of summary statistics (gcollapse), identifying distinct levels of a variable (glevelsof), and much more. gtools uses a C plugin and is even faster than ftools for tasks that can be performed using both suites of commands. gtools is available from the Statistical Software Components (SSC) archive, and you can read all about these commands here.