Many advertisements have an extremely dangerous level of flashing lights, and all of them pop up without warning and they can and do trigger epileptic seizures as a result even in perfectly safe streams.
This is an extreme concern for many people, including myself.
There is a specific advertisement that has so much flashing it can trigger a seizure even for someone using medication because of it being so hazardous, that ad promotes audible.
I tried reporting it to them for how dangerous it is but they do not accept feedback of a complaint category.

I would like to request that some sort of check be made on all advertisements for flashing and swift contrast transitions (since contrast transitions are also a type of trigger flash) and I would also like if a timer or warning somewhere on screen could be added to provide users with foreknowledge of when an ad will begin playing.

It is good to support twitch and streamers, but people with epilepsy may end up having to use adblockers if all the ads stay obnoxiously dangerous.