Suggested Farm #2: Use the quest Drakes on the Plain in The Floodplain of Mahnkelon. You have to take Koss with you, but if you want to get all the drops, you can flag him off the radar to the south. The first two groups of drakes consist of Irontooths and Steelfangs only.
Suggested Farm #4: Enter the Rhilon Refuge mission. Flag Master of Whispers to the north, then run south (do not trigger Dejah). After fighting one group of beetles, you will find two groups consisting of 4 Steelfang Drakes. There is also a third group nearer the waterworks, but you have to run past or kill one or two groups of Kournans.
Threats & recommended skills
Threats: general threats like hex, condition, environmental effects etc.
Tactics: important tactics, for example pulling, choke points etc
Recommended skills: skills like anti-kd, hex removal etc
Suggested Solo #1: Spirit spam can farm Drakes on the Plain easily.
Suggested Solo #2: 55 work excellent during Drakes on the Plain quest