replacement parts

I've had issues with temp creep only when idle when stopped at long red lights. Before I replace anything like the fan clutch I was looking around to make sure there wasnt any obstructions and I noticed ths upper seal in between the front grille and front of the radiator is lodged/fell. Im going...

What are some aftermarket brands people have used to replace factory parts, and what parts would you not mind not being genuine Mopar items? I agree with most here that sensors should basically always be Mopar since the aftermarket ones can cause erratic behavior, but what about other wear...