These guys that call themselves Agartha are streaming their whole album. The music is something like progressive black or death metal. It is pretty hard stuff for those who like that.
With Leprous comes a Norwegian progmetal band that has gotten a lot of nice critiques with their last album. It is pretty hard for being melodic prog metal:
Mnemic is a pretty hardcore metal band that has both screaming and mellow vocals:
Here comes a theme based space metal opera about a travel in space and time. It is a very melodic and easy listening piece of metal music:
Here is some pretty catchy, yet rough metal with the Devin Townsend Prjoject - Deconstruction. The video is pretty funny as well:
If you still have not listened to Myrath I would recommend to do so:
Personally I like their earlier work better.
If you like very catchy and melodic metal that has a similar sound to a lot of pop music you should check out Saint Deamon. They are a great live band: