I lately discovered Whorion, a Sympho-Technical Death metal band from Finland;
https://www.youtube.com/watch?v=03IZeQYvfwI

Or Duskmourn, a Melodic/Atmospheric Death Metal ( but also include Epic Metal elements) band from USA; These bands both released only one EP and one LP, but they are absolutely worthy;

https://www.youtube.com/watch?v=eRO9BVxLBJk

Also, I came into Swallow the Sun; they are now an affirmed Doom-Death Metal band from Finland, they are going to release soon a triple album, if you like gloomy and melancholic atmospheres they are the perfect band!

https://www.youtube.com/watch?v=8ZY6nNNGQME

Finally, the most surprising, jaw-dropping band I found out lately are Ahab, a 'Nautik' Doom Metal band ( Includes elements of post metal, atmospheric, and are mostly regarded as funeral doom) I felt in love with them..

https://www.youtube.com/watch?v=xTVwqRJnNBY