Text taken from eve.podzone.net, great site


*** Damage types of NPCs ***
Amarr Navy = EM/Thermal
Angel = All (Explosive-kin)
Blood Raiders: EM / Thermal
Caldary Navy = Kinetic/Thermal
Centii: EM / Thermal
Federation Navy (Gallente) = Kinetic/Thermal
Gistum: EM / Explosive
Guristas = Kin/Therm Kinetic mostly
Khanid Kingdom = EM/Thermal
Minmatar Republic Fleet: Explosive / Kinetic
Mercenaries = EM/Thermal/Kin
Mordus = Kinetic/Thermal
Republic Fleet (Minmatar) = All damage types
Rogue Drones = EM/Thermal (Mostly EM)
Rogue Pirate: Explosive / Kinetic
Sansha = EM/Thermal
Serpentis = Kinetic/Thermal
Seven: EM / Thermal
Thukker = Exp/Therm/Kin
Zazzmatazz = All (heavy kinetic/thermal)
*** DAMAGE VULNERABILITY OF NPCs ***
Amarr Navy: EM (S) / Explosive (A)
Angel Cartel: EM (S) / Explosive (A) (or thermal allround)
Blood Raiders: Thermal (S/A)
Caldary Navy: Explosive (or kinetic/thermal allroun