Good things to know (thanks to Lan Caurdinaeu)

** Damage types ***
Guristas (caldari)- Kinetic / Thermal
Serpentis (gallente) - Thermal / Kinetic
Blood Raider (amarr)- Thermal / EM
Sansha's Nation (amarr)- EM / Thermal
Angel Cartel (minmatar)- Kinetic / Explosive /
Thermal
Minmatar Fleet - Thermal / Explosive
Amarr Navy - EM / Thermal

***Hardeners to use***
Angel - All
Amarr Navy - EM/Thermal
Blood - EM/Thermal
Caldari navy - Kinetic/Thermal
Gurista, Mordus, Gallente - Kinetic/Thermal
Khanid - EM/Thermal
Mercenary - EM/Thermal/ (Kinetik (missiles)
Mordus - Kinetic/thermal
Odamian - Kin/therm
Rogue Pirate - EM/Explosive/Kinetic
Sansha - EM/Thermal
Serpentis - Kinetic/Thermal
Zazzmatazz - all types of dmg

***Damage types to use***
Angel - EM(shields) Explosive(Armor), or thermal all round
Amarr Navy - EM (shield) Explosive(Armor)
Mordus - EM (shield) Explosive(Armor)
Gurista - EM(shield