This article introduces the demonstration of several compact millimeter wave sources using both pencil and sheet-shaped pseudospark (PS)plasma electron beams. There are four devices that were successfully driven by PS plasma-sourced pencil beams, including a Ka-band Cherenkov maser, two backward oscillators (BWOs) in W-band and G-band, and an extended interaction oscillator (EIO) in W-band. There were also two devices successfully driven by PS plasma-sourced sheet electron beams, including two planar EIOs in W-band and G-band. These devices can generate tens up to kilowatts of output power, which are very attractive for many important applications. This article will especially present the recent advances in the generation of high quality PS plasma-sourced electron beams using a compact post-acceleration unit and the application of the beams in compact circular and planar EIO slow wave structures.