This guide is written for Update 17.7.1This build focuses on buffing Hysteria, keeping drain low and damage high, while mostly ignoring area buffs and debuffs. It utilizes two forma in its basic form (adding two Vazarin polarities), and four if you're using Primed Continuity and Flow (adding a Madurai and Naramon polarity). All of the mods I use are max rank.
Aura: Steel Charge
This aura's high mod capacity bonus and buff to our Hysteria damage make it irreplaceable
Exilus Mod: Rush
Valkyr's high base movement speed make this a pretty good option, but Firewalker can also be considered
This mod is pretty amazing with Hysteria considering the fact that duration mods now lower the rate of energy drain on relevant abilities, and that the reduction in range positively effects hysteria by reducing the radius of the feedback component. The reduction in range can be largely ignored on other skills as we don't really use Warcry as more than a self-buff, Paralysis unless mobs are close, and Ripline still has a respectable range.
This mod's crazy amounts of Power Strength is worth using several mod slots to counterbalance it. With Narrow Minded, Continuity, Fleeting Expertise, and Streamline, we can basically ignore the Power Efficiency loss and simply enjoy the strength.
This is the only survability mod I use because Valkyr has naturally high armor, and her base shields are too low for Redirection to be worth it. You spend pretty much the entire mission in hysteria anyway.
Speaking strictly of energy drain, this mod may seem like a wash in terms of drain reduction, but when used in conjunction with Duration and Streamline it's pretty effective.
Necissary for keeping drain low
Free damage, self-explanitory
This keeps us in Hysteria during droughts of our precious energy balls
Same as Continuity, gotta keep that drain low