I am going to post metal, but nothing excessively heavy going. Can't see a lot of people appreciating the likes of Livelover.

Anathema (post-rock, avoid the first two albums as they switch genres afterwards)
Dream Theater (progressive metal)
Harmaja (folk rock)
King Diamond (heavy metal)
Alcest (shoegaze/'blackgaze')
Empyrium (folk/doom/'neofolk')
Ghost (heavy metal, also known as Ghost B.C)
Green Carnation (acoustic/progressive rock)
The Pains of Being Pure At Heart (indie pop)
Random & Lost Perception (hip hop)
Evergrey (progressive metal)