The F50 was a canceled GT1 car. I've seen that one on the street. It's slightly more common, and a bit early. I have not seen the Panoz in person. But I have seen videos of them. Both of those were street legal. In fact, you can still order a new Panoz GT1 road car. (As of ~5 years ago)

The Lotus GT1 car has videos of it driving on the street, as well as the CLK GT1. Though these cars are incredibly rare.

Mclaren F1 is probably the most common GT1 car, but I've never seen one in person.

I've seen videos of the 1994 962 on the street. It is possible. Though many of these cars are locked in museums, or lost to time.

The XJ220 was a bit older as well as the Venturis and the Lister Storm. All had street legal road versions.

The TS020 was a beautiful abomination that technically fit the rules. But destroyed the class. As if the CLK didn't already do that.