Design, simulation and test of four types of thermionic DC electron beam guns; hairpin source, strip source, line source and disc source have been evaluated. Beam optics analyses were performed using SLAC electron beam trajectory program (EGUN) and CST Particle Studio (CST-PS). The guns are in diode configurations with planar geometry of the electrodes. The focusing electrodes were placed at the same potential of cathode without any extra biasing or Whenelt electrode. From these novel designs well focused and parallel beams of electrons with beam current (42mA-12A), emission density (5.04-6.72 A/cm2), power density (5.04×104-6.72×104 W/cm2) and normalized emittance (0.51-31.72 π-mm-mR) were obtained. The simulated results were verified by experimental tests at 10 kV of acceleration potential. The designs are simple and inexpensive. These guns are useful for metallurgical applications and for electron optical devices due to high current and power densities. Moreover, these are also useful for accelerator technology due to high emission and low emittance parameters