Here is my list. I dont know as much about DC as I do Marvel but I will answer with the heroes I know.
Hostage/Bank robbery - You are in a hostage situation at the hands of armed thugs. Not really super powered but armed and desperate.
Green Arrow
Cosmic threat - An alien invasion, Darksied, Anything from space
Green Lantern (Hal Jordan)
Demons - Demons from Hell.
Dr. Fate
Low Level super Powered villain - one of Dc's many super powered scrubs.
Hourman
Mid level Super Villain - One of the mid tier guys.
Flash
High level Super Villain - One of Dc's big bads.
Superman of course. Now just because he is like the strongest, but because when things hit the fan you need someone to inspire you. Someone that will let you know everything will be okay. Superman fills that role.
Magical threat - One of Dc's many magical threats. (I didnt add this to my Marvel thread because there is only one really go to magic guy.)
Shadowpact.