Several Revit versions ago, an add-in was available that could be installed separately from the standard Revit program. This add-in allowed users to add standard configurations of steel connections to their model. In its early form, there was not a lot it was able to offer. Then in last year's release of Revit 2018, this Steel Connections tool was added to the interface on the Structure tab. It included over 125 parametric standard connections that could easily be applied to steel elements. But it still required a separate installation of an extension add-in to gain access to these connections.
Now in Revit 2019, these standards are included in the standard installation. Plus, along with using these standard connections, you can now create your own Custom connections using this tool, which allows you to store them for later use, which improves productivity.