Son'a
The Son'a are a population of Ba'ku exiles who act as the primary antagonists in Star Trek: Insurrection.
Attributes
The Son'a seem to have no unusual characteristics for humanoids. Having originated from the Ba'ku planet, many are extremely old, having benefited from the rejuvenating effects of the metaphasic radiation while living there. Leaving the planet caused them to start aging normally, so they have used advanced medical technology to sustain themselves.
Organization
The number of Son'a isn't known: those present on the So'na warships during ST:I may represent the entire So'na population. As such, their organization would be a military dictatorship.
Threat Assessment
The Son'a have access to technology comparable to that of the Federation, but there appear to be only a handful of Son'a. Their entire fleet apparently consisted of three warships. This would make them a minor power by most standards.