The name for a metalcor/deathcore band needs to be catchy and unique. This is what will catch the fans first. To find the best name get the band members, friends and family together and do some brain storming. Come up with an easy name to remember but one that will stand out, such as Metal Heart or something along those lines.
The best names combines two terms with one something unique about the band and and something about the genre. A few ideas: Angel Autopsy, Heaven's Falling, Perfect Plague. A name is not as important as the music.