reverse upper cable flies, reverse middle cable flies, reverse lower cable flies, do these in supersets, its hard as fuck and target all parts of ur traps, but make sure ur arms are straight the entire time or else ur triceps wil be doing most of the work (no bueno) fucking farmers walks, but make sure to retract ur scapula anytime doing them or shrugs, this will also work ur levator scapula muscles and ur delts just by holding the weights, ur forearms will get pretty jacked up too. Rows will also work ur traps, btu mostly ur lats and teres major muscles, god i love busting out some traps burns soooo good