What are the three migraine injections?

Excuse me, I'm curious to know about the three migraine injections that are commonly used. Could you please elaborate on each one? Are they all equally effective in treating migraines? Are there any specific scenarios where one injection might be more suitable than the others? Additionally, what are the potential side effects and precautions one should take before using these injections? I'd appreciate it if you could provide a concise yet comprehensive overview of these migraine treatments.