Good metalcore and screamo bands that not many people have heard of. Check them out when you get a chance.

Greeley Estates- Metalcore. They live in Phoenix, Arizona, which isn't far from me lol.

Enter Shikari- A metalcore/post-hardcore and electronica band from the UK.

Four Year Strong- Well, there a punk band, but they're good so I posted them :P.

Blessthefall-Metalcore. They're also from Arizona.

I Killed The Prom Queen-Metalcore band from Australia.

Alesana-Metalcore band.

Underoath- Metalcore band.

Some good bands that most people have heard of lol.

Asking Alexandria- Metalcore and electronica band from the Uk.

Bring Me The Horizon- Metalcore band from the Uk. Some of their older stuff is deathcore.

The Devil Wears Prada- Metalcore band.

A Day To Remember- Metalcore band.

These are just some bands I recommend :). They're all really good.