Every block that doesn't emit light must be shaded, but some aren't. Here is a list of every block that should or shouldn't be shaded, and where it needs work:

-All mob skulls: Don't emit light, should be shaded (Inventory only);
-Conduit: Emits light. It shouldn't be shaded (World only);

-Dragon Egg: It's a strange one. Doesn't emit light, it isn't shaded in the inventory and is bright when held or dropped, just like other blocks and items that emit light. I genuinely don't know what is right or wrong about this item.