I'm sure you already know the commons (i.e. Dimmu, Borknagar, Emperor, etc.). That said, you may already know lots of these as well.
Here are a few that I usually think are a bit more under the radar:
Black Lotus (reminiscent of Borknagar, in some cases)
Antiquus Scriptum (clean vox usually in a choir-esque form)
Enid (these guys are weird; they play black metal, but when they utilize clean vox they shift to a kind of symphonic gothic, or something weird)
Negura Bunget
Nokturnal Mortum
In Lingua Mortua
Ancient Rites