We already have such a repository for storing model elements, and they are accessible via the Model Explorer. To show the Model Explorer, simply click View > Panes > Model Explorer from the toolbar.
This article teaches you how to reuse model elements using the Model Explorer:
And with lots of model elements in the repository, you’ll likely want to organize them better. Visual Paradigm suggests using Model to group related model elements, here is an article that teaches how (it uses Project Browser, but working with Model Explorer is very similar):
In this project I just made a (small) Use Case diagram in another model (using the project browser’s ‘Model structure’ tab), and in the picture above I’m starting a new diagram. I double clicked on the canvas to open the Resource Catalog, I selected the actor model but then I did something special: instead of entering a new name I pressed control-space, see above.
What this does is list every other related model element in your project. In my case this is an actor I named after myself. So if I want to re-use this element all I have to do is press cursor down to select it, and press enter (or you can click on it too of course).
This is an even faster way of reusing your items. And the best part (in my opinion) is that you don’t even have to think about what to use, because VP will ensure that you only get to see relevant models.