The Dalek drone was the most common Dalek model. (TV: Victory of the Daleks, GAME: City of the Daleks) They were used as the main "foot soldier". These red daleks sometimes even outranked white ones on order of the Emperor. They often headed missions too.
The Daleks which escaped the destruction of the Crucible (TV: Journey's End) camouflaged themselves as "Ironsides" which were supposedly created by Edwin Bracewell. These Daleks were khaki-green coloured, probably because it was a self-applied paint job in order to perpetuate the deception that they were obedient war robots. Following the restoration of the Dalek race, the standard Daleks became a bright red colour, but were otherwise no different from their superiors. The "Ironsides" were then destroyed by their "superior" successors. (TV: Victory of the Daleks)
A Dalek drone was present when the Doctor was locked in the Pandorica along with a Supreme Dalek and an Eternal Dalek. The Pandorica Opens When the universe ended, the Daleks were erased from history, with only two Stone Daleks remaining as "fossils in time". It might have been the Dalek drone that was reactivated. (TV: The Big Bang)
While the design of the New Dalek Paradigm drone was mass-produced for some time, (GAME: City of the Daleks, COMIC: The Only Good Dalek) the Daleks ultimately chose to return to using the previous bronze design as the standard foot soldiers; the red Dalek variants became an 'Officer' class, while their bronze subordinates served as the drones. (TV: Asylum of the Daleks) These bronze drones were sometimes sent on missions where they operated without the leadership or presence (although still under the instructions) of New Paradigm commanders. (COMIC: The Dalek Project, PROSE: The Dalek Generation)