The Retired and Active Players screen (League Menu >> History section >> Recently Retired Players >> Retired and Active Players tab) lists all players from the currently selected league, BOTH retired and active:

This screen is primarily of interest to GMs who wish to look at statistics across retired and active players, for example to sort by the most home runs, etc.

On this page, you can take advantage of OOTP's Views, Filters, and many of the Common Drop-Downs. Review those sections to get a better understanding of how to manipulate the data on this screen to suit your needs.

Commissioners also have the ability to unretire players.