The HUniverse is a big place. Fortunately (unlike some other comic events) HUniverse stories are written so you don't need to read everything to understand what's going on.
However, if you do want to, this is a guide to reading HUniverse titles in the order that makes most sense.
|Pre-Heroes Unite #1||
Hellfire (sadly no longer available)
|Introduction of Hellfire|
Acrobat - Issue #1
|Introduction of Acrobat|
|Energize Series 1 - Issues #1-3||Introduction of Energize|
|Heroes Unite #1||Heroes Unite - Issue #1||Introduction of Heroes Unite|
|Pre-Heroes Unite: Cavalry||Bombshell - Issue #0||More about Bombshell|
From Comet Kid: Team Players to Comet Kid: Shooting Stars
|Introduction and Origin of Comet Kid|
|Acrobat - Issue #2 to Acrobat: Plot Twist and Tech||Introduction of Plot Twist|
|Heroes Unite: Cavalry||Heroes Unite: Cavalry|