Best Tank for Npc's:
Amar/Raiders/Khandid/Sansha - EM/Therm
Caldari/EoM/Odamian/Serpentis - Therm/Kin
Gallente/Gurista/Mordus/Syndicate - Kin/Therm
Angel/Republic/Thukker - Exp/Kin
Rogue Drones - Exp/Kin/Therm
Merc/Sleepers/Concord - Omni


Best Damage to NPCs:
Angel/Thukker - Exp
Caldari/EoM/Gurista - Kin
Merc - Therm
Blood Raiders/Sansha - EM/Therm
Syndicate - Kin/Therm
Rogue Drones - EM
Mordus/Serpentis - Therm/Kin
Concord - Kin

Combat sites grading (more like my shields where are my shields, easiest -> toughest)
Faction: Hideaway* > Burrow > Refuge > Den* > Yard > Rally Point* > Port > Hub* > Haven > Sanctum (Low and null sec)
* 4 levels of difficulty available standard > hidden > forsaken > forlorn

Drone: Cluster > Collection > Assembly > Gathering > Surveilance > Menagerie > Herd > Squad > Patrol > Horde (low and null sec)