Mostly just charged melee / bow abilties. For example if you try and use Poison Arrow from Sneak, you will notice it does not count as a sneak attack, whereas Snipe does. Medium and Heavy attacks also work from Sneak, as do skills like Ambush (nightblade), Uppercut (2h), Flying Blade (dual wield), and a few others. You will just have to test things out. Staves don't work nor do spells like Crystal Shards (sorc, I could only imagine the tears...).

There are magicka based abilities that do crit from sneak such as Teleport Strike (base line NB).