So far I'm sure of
I'm pretty sure of (but need to confirm and expand)
Some audio control / detection
Some graphic manipulation / pixel control
Some graphic things that can be done without GPU / Direct X
Anyway, here is my start. If anyone has some obvious ones to add to the list, please do!
(As an aside, this list would be nice for just the general hey-I've-heard-Flash-is-dead-from-some-blog passers by)