The hardest dudes have the shittest names - true story.

(Faction) Burrow / Drone Collection (lowest)
(Faction) Hideaway / Drone Cluster
(Faction) Refuge / Drone Gathering
(Faction) Den / Drone Gathering
(Faction) Yard / Drone Surveillance
(Faction) Rally Point / Drone Menagerie
(Faction) Port / Drone Herd
(Faction) Hub / Drone Squad
(Faction) Haven / Drone Portal
(Faction) Sanctum / Drone Horde (hardest)

** Damage types ***
Guristas - Kinetic / Thermal
Serpentis - Thermal / Kinetic
Mordus legion - Thermal / Kinetic
Blood Raider - Thermal / EM
Sansha's Nation - EM / Thermal
Angel Cartel - Kinetic / Explosive / Thermal
Minmatar Fleet - Thermal / Explosive
Amarr Navy - EM / Thermal
Mercenary - Em / Kinetic / Thermal

Best Damage to NPCs
Guristas - Kinetic
Serpentis - Thermal
Mordus - Thermal & Kinetic
Blood - EM & Thermal
Sansha - Thermal
Angel - Explosive
Mercenary - Thermal