GMC Jimmy OIL LEAK

None of the things you listed will leak real fast. For fast leaks suspect the oil pressure sending unit or the rubber gasket under the oil filter. The gaskets you replaced will typically cause a small spot under the engine where you park, not big puddles. Look for the highest place you find oil on the engine. There is also dye that can be added to the oil after washing the outside of the engine. After driving far enough to make the leak show up, you search with a black light. The dye will appear as a bright yellow stain.

It doesn't have a special name that I'm aware of. If you tell the people at the auto parts store what you're trying to do, they will find the product. The bottle is only about an inch in diameter and about two and a half inches tall. The liquid is dark purple. When you search with a black light, it will show up bright yellow.