Let me add to the excellent list:

TMJ problems.

TMD is the disorder of your temporo-mandibular joint being out of place. Your jaw can be off a hair's thickness and cause real issues if you are senstive. If you grind your teeth, or wake with a sore, achy jaw, if it spasms sometimes while you chew making you bite your cheek or tongue, then you may have a problem.

If a dentist pulls back teeth, especially molars, haphazardly, then he can cause TM (by using the rest of your jaw for leverage, for example.) If you get hit in the jaw, especially from the very front, by a fist or a ball, it can cause the joint to go off.

If you get a headache or jaw ache after eating foods like an apple or steak, you might have TMD.

If you can't open your mouth wide enough for 3 fingers to fit into it, you might have a problem with your TMJ.

Sleeping
with inadequate support of neck and head can also cause migraines. (Especially if it causes you to hold your jaw "funny" while sleeping. Sleeping on your side can do it too, with excessive pressure on one side of your jaw.

Keep track of when you have migraines, or when the prodromes or auras come, and see if you can figure out why.

As Sabby said, bright or flickering lights can cause migraines. Florescent lights are known for this, as the light isn't filtered by the eye like incandescent lighting is.

Also, reds and oranges in bright hues, in abundance,(clothes, furniture, paintings) or in scrolling text especially with blue text cause not only migraines but seizures too, in susceptible people.

Taking medicines that open blood vessels can cause migraines. That's what a migraine actually is, too much blood flow to the brain, which is why caffeine and ice packs can help at times.