^I'm surprised you think the Vomnin would go on a list of "angry powers." They're not particularly aggressive, and in fact are one of the more responsible and constructive societies in the Gum Nebula region, participating in major peacekeeping efforts like cosmozoan regulation. And we know from Watching the Clock
that their cooperation with other major powers -- including the Federation -- to guard against threats to galactic safety continues into the future.
Of the Gum Nebula powers I established in Orion's Hounds
, the most warlike and irrational would be the Fethetrit.
And we don't really know if the Fen Domar are "angry," just that they got into a battle with Voyager
in the "Endgame" future and damaged Janeway's favorite coffee cup. We don't know if that battle was the result of Fen Domar aggression or a simple misunderstanding of the sort that underlies many battles in Trek. Maybe they just had a cultural taboo against caffeinated beverages.