Fictional Political Party: Actually, a remarkable number of them – which has a lot to do, I suppose, with the cyberdemocratic/sortitive (random selection) nature of the Imperial Senate and most local assemblies making running a conventional political party a giant exercise in futility; they function mostly as debating societies, influence brokers, old-boys’ networks, and direct-action organizations, although the larger ones do manage to coordinate a few votes among their members who are conscripted into the legislature.
As such, they tend to be organized around a single issue they care about, or at least a philosophy, rather than being the corrupt and incoherent conglomerates of a dozen disparate positions that we all know and presumably love.
A few of the many, many examples would include the:
Above All, One Imperium Movement (consolidation of the entire rest of the Galaxy)
Alliance for Balance (avoidance of extremism, ensuring that what is done is done well)
Bricklayers of Utopia (mostly direct-action, but a general policy of utopia through innovation)
Party for Efficiency (minimize overhead, run the Empire like a successful business)
Sanguinary Enforcers of the Liberty Ethic (still fighting the old-time revolution; destroy all non-Societies of Consent, everywhere)
Status Quo (professional devil’s advocates; ask difficult questions to challenge all change because the status quo is already pretty damn good)
Universal Indifference Society (isolationists; barbarians are disgusting and we don’t want any on us)
And so on and so forth…