Are great trap muscles built by doing heavy compound movements (like deadlifts) or should they have exercises dedicated to them (like shrugs)?
While you are most likely referring to the superior or upper trapezius muscles, there are actually three different sections of the trap muscles and it is important not to neglect any particular group. With that being said, however, if you want total trap development then heavy deadlifts alone aren't going to cut it and neither will fast reps of heavy shrugs. The key to building "monstrous" traps is time under tension. Shrugs with a 3-5 second hold at the top are terrific, all the while contracting the traps at the top of the motion.
Additionally, farmers walks cannot be neglected in upper body training. They can be done with a hex-bar, or dumbbells but the key factor is to go as heavy as possible for as long as possible. Not only will you light up your traps, but you will also strengthen your forearms, core, and upper back.
If you are still looking for more exercises, I would suggest trying heavy but controlled rack pulls in tandem with your farmers walks, deadlifts, and shrugs. If you run a circuit of these core exercises, all the while maintaining proper form and contraction, you will look like an Olympic wrestler in no time!