Updating the list...
Half stops:
#06 Pemberton
#15 Barlow, Boy's knife
#23 Pioneer
#25 Ez-Open, Jack
#45 Lumberjack
#47 Hayin Helper
#48 Trapper, Single Bladed Trapper
#54 Harness Jack, Cigar Whittler, Big Jack
#61 Congress, Half Congress
#62 Easy Pocket Congress
#65 Ben Hogan (slipjoint)
#71 Sodbuster
#72 Cody Jack (slipjoint)
#73 Scout, Jack
#74 Wharncliffe Trapper
#85 Bullet End Jack
#92 Eureka Jack
No half stops:
#12 Toothpick
#16 Canoe
#23 Bull Lock (back lock)
#33 Conductor (2 blade)
#36 Sunfish
#53 Cuban Stockman, Muskrat, Furtaker Trapper
#56 Dogleg Jack
#65 Ben Hogan (lockback)
#66 Serpentine Jack, Calf Roper
#68 Pony Jack, White Owl
#72 Lockback
Mixed:
#33 Whittler (whittler) half stop on secondary blades but not main blade
#62 Courthouse Whittler half stop on secondary blades but not main blade
#89 Executive Whittler has Half Stop on main blade but not on secondary blades.