Today we have a very sleek Heretic model built by AdamKop. As you can see from the comparison shots beneath, the design stays close to the in-game model. It's a little bit less weathered than most versions we encounter, which comes across as nice and clean. The motion blur and engine effects are also a nice bonus!
From left to right: the in-game model, the front box cover and a 1995 promo shot.