Old classics, now irrelevant:
Buck110
Ka-Bar USMC Knife
Victorinox 40P
Case Peanut
Opinel No 5
Schrade 1080
Schrade SP2
Mid-century advancement:
Buck 110 one-arm bandit - one hand opening
Buck quick-draw sheath - "auto" open folding knife from pocket/sheath
USAF Pilot Survival Knife - Knife designed to pry, saw, and baton
Spyderco Worker - integral one hand open and close
Boye Cobalt Folder - rust proof folding knife
Victornix keychain knife - blades to the masses
Parker Stockman - japanese knives designed and imported by American company on large scale
Gerber Bolt-Action - injection molded handle, one hand open and close refinement
Chris Reeve Sebenza - titanium framelock, knives as "expensive" products with high standard
Moderns:
Benchmade 720 - aluminum handle mass production, popularized axis lock
Benchmade 750 - titanium framelock mass production
CRKT M16 - popularized flippers
Emerson Commander Wave - further refinement of "auto" open folder
Spyderco Pacific Salt - H1 steel, rust proof with more acceptable sharpness/edge retention
Chris Reeve MKVI - one piece hollow handle
RAT-3 - EDC size full-tang fixed blade
Kershaw Leek - assisted opening
CRKT Ripple - popularize IKBS
Spyderco Mule - designed specifically to test different steels in the same form factor
Post-Moderns:
Ganzo 720 - Chinese knock-off knives are now "good"
Cold Steel American Lawman - tri-ad lock
Medford Praetorian - titanium framelock, visual design cues over pure function
ZT0456 - steel lockbar insert for titanium flippers
ESEE-6 - full-tang fixed blade designed to pry & baton
Spyderco Manix Maxamet - ultra-high performance steel in a small & relatively inexpensive folder
Just a list off the top of my head