Quoted from solarvalue:Probably 1980 but 1981 was great as well, see below:
Barracora
Black Knight Limited Edition
Catacomb
Centaur
Dragonfist
Eight Ball Deluxe
Elektra
Embryon
Fathom
Fireball II
Flash Gordon
Frontier
Jungle Lord
Mars God of War
Medusa
Pharaoh
Solar Fire
Spectrum
Add the other Stern classics to Catacomb and Dragonfist.
Ali
Meteor
Big Game
Cheetah
Nine Ball
Seawitch
Galaxy
Lightning
Iron Maiden
Viper