A recent items list is a great way to quickly access applications, documents, servers, and whatever else you tend to frequently need. macOS includes an option to search for this stuff in the menu bar, but How-To Geek points out a way to add a special icon to your Dock.
To add the new icon to your Dock, open Terminal (Applications > Utilities) and type this in:
defaults write com.apple.dock persistent-others -array-add '{ "tile-data" = {"list-type" = 1; }; "tile-type" = "recents-tile";}' && \killall Dock
This adds an icon to your Dock that includes recently opened apps by default. If you’d prefer to see a different file type, right-click the icon, then select the new type of files you’d like to see in the Dock. You can choose between applications, documents, servers, volumes, and items (which just includes everything of every type). You can adjust how many items appear here by heading to System Preferences > General and setting the Recent Items dropdown to whatever you want.
Quickly Open Recent Apps and Documents With This Hidden Mac Feature | How-To Geek