As far as I'm aware, no Autocast skill is AOE based, though they perhaps can be simulated with target dummy and some tricking for forcing the Autocast. This is quite annoying though and result in it's unusable outside of Autocast.
And what has been said before is true, channel can't be made Autocast and that's the MOST configurable spell existed in Warcraft 3. Though I haven't run tests myself, but as far as I'm aware, it's not possible making non Autocast spell an Autocast one.
Also, most Autocast are unit target (Heal, Inner Fire, Slow, Searing/Frost/Black Arrows, Faerie Fire, and so on).
Some don't have target, such as Raise Dead, Essence of Blight and Spirit Touch.