Enemies ------- Hardener to use ---------- Damage type to use

Blood Raider --- EM/Thermal --------------- EM
Guristas ------- Kinetic/Thermal ------------ Kinetic
Sanshas ------- EM/Thermal --------------- EM
Serpentis ------ Thermal/Kinetic ------------ Kinetic
Angel. --------- All Resist (Explo/Kin) ------ Explosive
Mordus -------- Kinetic/Thermal ------------ Kinetic
Rogue Drones -- All Resist (Explo/Kin) ------ EM
Mercenary ----- All Resist (EM, Therm) ----- Thermal
Minmatar. ------ All Resist ---------------- Thermal, Explo
Gallente. ------- Kinetic/Thermal (sec. EM) -- Thermal
Amarr --------- EM/Thermal. -------------- Thermal
Caldari -------- Kinetic/Thermal ------------ Kinetic

There are 10 different types of Anomaly Class - Class 1 (easiest) to Class 10 (hardest).
Class 1 = (Faction) Hideaway or Drone Cluster (easiest)
Class 2 = (Faction) Burrow or Drone Collection
Class 3 = (Faction) Refuge or Drone Assembly
Class 4 = (Faction) Den or Drone Gathering
Class 5 = (Faction) Yard or Drone Surveillance
Class 6 = (Faction) Rally Point or Drone Menagerie
Class 7 = (Faction) Port or Drone Herd
Class 8 = (Faction) Hub or Drone Squad
Class 9 = (Faction) Haven or Drone Patrol
Class 10 = (Faction) Sanctum or Drone Horde (hardest)