Is there a script that performs this function, for example I select several clips and the script identifies which of them are repeated more than once throughout the project and deletes all duplicate clips leaving only 1 of them
First, you need to define "duplicate".
The big question is, are we talking "exact duplicate" or "partial duplicate" or just anything from the same media?
And then how do we want it to work?
Is there a script that performs this function, for example I select several clips and the script identifies which of them are repeated more than once throughout the project and deletes all duplicate clips leaving only 1 of them
Vegasaur's Project Audit identifies duplicate events, but an identified duplicate event doesn't mean of itself that one of those events needs to be deleted. What about if an event has deliberately been repeated (e.g. "Let's see that again"). Or if a direct copy of a video event has been dropped onto a lower track for an FX/masking purpose?
You could always use Vegas Pro's Project Media window option "Select Timeline Events" to find duplicated events, but Vegasaur's Audit scan is much faster and easier to use with it's "Go To" choice to explore the duplicate event to make sure whether or not it should be deleted. Vegasaur also has "Punch In" detection which identifies if two media events are overlayed over one another on the one track.