Damage to tank:
Guristas - Kinetic / Thermal
Serpentis - Thermal / Kinetic
Mordu's Legion - Thermal / Kinetic / EM
Blood Raider - Thermal / EM
Sansha's Nation - EM
Angel Cartel - Explosive / Kinetic / Thermal
Mercenary - ALL
Rogue Drones - ALL
Amarr Navy - EM / Thermal
Caldari State - Kinetic / Thermal
Gallente Navy - Thermal / Kinetic
Minmatar Fleet - ALL (varies)

Best damage to deal against NPCs
Guristas - Kinetic
Serpentis - Kinetic
Mordu's Legion - Thermal / Kinetic
Blood Raider - EM
Sansha's Nation - EM
Angel Cartel - Explosive
Mercenary - Thermal
Rogue Drones - EM
Amarr Navy - Thermal
Caldari State - Kinetic
Gallente Navy - Thermal
Types of missions available

Administration: 50% Kill, 50% Courier
Advisory: 34% Kill, 66% Courier
Archives: 5% Kill, 90% Courier, 5% Trade
Astrosurveying: 40% Kill, 30% Courier, 25% Mining, 5%
Trade
Command: 97% Kill, 3% Courier
Distribution: