Carlin for Willi Wasp
Edron for Orshabaal (notably Morshaabal and Feroxa don't work)
Hrodmir for Ghazbaran
Northern Darama for The Pale Count and Zomba (and The Mutated Pumpkin during its event, but only its first spawn right after each server save)
Roshamuul for Gaz'haragoth
Vandura for Ferumbras and Morgaroth (and Devovorga during its event)
Zao for Cublarc the Plunderer, Chizzoron the Distorter, Grand Mother Foulscale, The Blightfather and Zulazza the Corruptor
The Abomination is missing on this list. Initial reports say it won't be notified neither, but I will wait for a first-party confirmation.