There are three main groups:

The Bolivarian Militia: Literally just a militia that helps the army and police, basically reserve units that exist to protect in case of a coup like in 2002.

The Colectivos: Armed Civilians who support the goverment but have no tie with the Police or Army, these pre-dates Hugo Chavez's goverment.

The Bolivarian Forces of Liberation: A very small guerrilla army that exists in Venezuela and seems to give critical support to the goverment, they barely controls anything and exists more or less as a local paramilitary organization for the state of Apure's goverment.