Cosmic anomalies are ranked in difficulty by 10 levels, these are:

(Faction) Burrow / Drone Collection (easiest)
(Faction) Hideaway / Drone Cluster
(Faction) Refuge / Drone Assembly
(Faction) Den / Drone Gathering
(Faction) Yard / Drone Surveillance
(Faction) Rally Point / Drone Menagerie
(Faction) Port / Drone Herd
(Faction) Hub / Drone Squad
(Faction) Haven / Drone Patrol
(Faction) Sanctum / Drone Horde (hardest)

Main damage types that should be used against these rats:
Guristas (Caldari) - Kinetic
Angel (Minmatar) - Explosive
Blood (Amarr) - EM/Thermal
Sansha (Amarr) - EM/Thermal
Serpentis (Gallente) - Thermal
Khanid (Amarr) - EM/Thermal
Mordus (Caldari) - Kinetic/Thermal
Mercenary - Thermal
Amarr Navy - Thermal
Caldary Navy - Kinetic
Gallente Navy - Thermal
Minmatar - Thermal
Thukker - Thermal
Roque Drones - EM/Thermal
Komni - Thermal