Simple categories matching soviet:

• agency,
• institution,
• system,
• union,

Members with property soviet:

• superpower,
• kgb,
• kolkhoz,
• gerontocracy,
• tank,
• army,
• brigade,
• subsidized_housing,
• secret_legislation,
• utility,
• former_member,
• school,
• militia,
• welfare_system,
• university,
• medium_control,
• network,
• sport_hero,
• kazakh_cf,
• trade,
• soviets,
• presidium,
• residential_school,