Sneezing, coughing, crying, getting upset, orgasiming.
As well as bright lights and overly noisy environments.

noise
smells/chemicals even if I can't smell them
severe stress/BP spikes
sleep apnea
hypoventilation from heavy doses of opiates

before jaw surgery: any valsalva trigger like cough, crying, shouting, singing, talking. my CPAP machine.

if a cold makes you worse, it's probably because it is increasing your sleep apnea, and you need to get control of that trigger. doing so made a huge difference for me.

Cafine is a huge one for me! Sadly, as a good latte is an awesome stress reliever for me which stress is a huge trigger for me. I am also finding that vitamin a is a trigger which is tricky to avoid when trying to eat healthy. Salt. Not getting enough sleep or to much sleep. And I am finding I have to take my meds at almost the exact same time. I have about a half hour window or I will wake the beast known as a headache. I am also noticing how much I do in a day will impact the next day. I haven't figured out that balance yet. To little and I am in pain, to much, same story. To much reading and my eyes are telling me about it with eye pain.

The two I can think of for sure are exercise and caffeine. But the opposite caffeine effect for me.... If I don't have it within an hour or so of waking up I get really bad whooshing and fullness in my head and behind my eyes.

my head likes caffeine. there is one obscure study that showed it reduces brain edema.

before jaw surgery exercise was a trigger but now it actually helps. if I make myself exercise when I have brain fog it will clear. I think if you make sure you are not valsalva-ing with exercise then light exercise might help.

Certain foods and drinks, bad posture, stress. If I think of anything else will post later.

Ditto to caffeine helping, however, back in the day it would put me down. Let me clarify which caffeine helps, quality coffee, no soda, red bull, chocolate,