I believe that the Dreadnought was from the old Assault on Black Reach or some other starter set. I 3D printed the arms and used some tubing for the Autocannons. The raven is an extra I printed when making the Corvus Storm Raven conversion. I don't know how much time these guys will see on the table, but they bring a lot of shooting.
I got a bit of paint on my converted (and taller) Raven Guard Centurions. I've placed them next to my converted Dreadnought for scale.