Man I stilll have a soft spot for the Exterminator - the sequal was a bit of a let down..
Some more:
(Vigilante Ladies)
Thriller A Cruel Picture
Savage Streets with Linda Blair
Others:
The 3 Punisher Films.
The Boondock Saints
Taxi Driver
Walking Tall (there's 3 of these and a remake - the first one is certainly a Vigilante film not seen 2/3)
Dead Man's Shoes
Theres also a bunch of films with cops who break the law and step into vigilante territory (mad Max/Buncha Steven Seagal films/Dirty Harry).
Theres lots of Blaxploitation Vigilante Films (these are just a few)
Black Belt Jones
Black Shampoo
Coffy + Foxy Brown
Slaughter
Disco Godfather