Faction Weaknesses Damage types dealt
Angel Cartel Explosive / Kinetic Explosive (62%) / Kinetic (22%)
Blood Raiders EM / Thermal EM (50%) / Thermal (48%)
Guristas Pirates Kinetic / Thermal Kinetic (79%) / Thermal (18%)
Mordu's Legion Kinetic / EM [1] Kinetic (70%) / Thermal (30%)
Rogue Drones EM/Thermal (varies) [2]
Sansha's Nation EM / Thermal EM (53%) / Thermal (47%)
Serpentis Kinetic / Thermal Thermal (55%) / Kinetic (45%)
Sleepers (Omni) [4] (Omni) [4]
Sansha's Nation (incursions) (Omni) [4] (Omni) [4]
Amarr Empire EM / Thermal EM (47%) / Thermal (42%)
Caldari State Kinetic / Thermal Kinetic (51%) / Thermal (48%)
Gallente Federation Kinetic / Thermal Kinetic (60%) / Thermal (39%)
Minmatar Republic Explosive / Kinetic Explosive (50%) / Kinetic (31%)

[1] ^ Kinetic damage is best, EM and thermal are both ~75% as effective as kinetic but EM is better against shields and Mordu's ships have active shields so it is better overall. EMP is best projectiles to use.
[2] ^ Rogue Drones have a tendency to vary wildly in what damage type they deal and are vulnerable to. Low-level missions seem to lean towards EM/Thermal while high-level missions lean towards Explosive/Kinetic. Consult mission reports about the specific mission or exploration site before undocking.
[3] ^ This refers to CONCORD enemies found in certain missions (particularly in low- and null-sec). CONCORD ships patrolling high-sec are invincible, so the damage types they do is not relevant.
[4] ^ "(Omni)" means that the ships do all damage types equally, or are equally vulnerable to all damage types.
[5] ^ Em/Th approx 75% as effective as kinetic. Explosive around 60% compared to kinetic. EMP the best projectile ammo
[6] ^ Unless in an Electrical or Exotic filament, in which case use EM or Kinetic respectively