I am in the metal scene. Here are 8 examples of things I wear.
Black or Blue Levi's Jeans (tailored to my fit)
Steve Madden black boots, black nike's, black/white converse, black/black converse
Black belt. Black watch with a white face (MVMT)
Shirts, I change a lot on. But I get a lot of compliments in it is pretty true in the hardcore scene. There's absolutely nothing wrong with a black t shirt, sleeves rolled up twice, and black jeans. Looks great. Never go light pair of jeans with a dark top though.
Today I wore blue jeans, black converses, black belt, charcoal t shirt and a green/white/black plaid shirt with the sleeves cuffed. Looked great, got a lot of compliments.
Last night at this local Dallas show for a few facedown record bands I saw lots of people sporting skinny jeans and plaid. I wore black skinny jeans, black boots, black t shirt with a deep crew neck, black hoodie and a black leather jacket.
Levi's denim jacket, or levi's denim jacket cut off into a vest are great. You can add patches or just sport them with a band t shirt. Throw a hoodie underneath and it adds some flavor.
With the hardcore scene you can really wear anything. It helps to wear clothes true to your size, I wear mostly black, and throw in some different necklines / crew, deep crew , V, tank.
Hope this helps give you some inspiration on what to look for or what works for me.