What type of bonds do good conductors of electricity have?

Metallic bonds would be better than ionic. With ionic bonds, the electrons can move but they tend to be held close to the cations. With metallic bonds, the valence energy levels overlap and the atoms have valence electrons that are shared freely by all the atoms. Metals are sometimes described as metal ions in a sea of electrons. In fact, the distinctive shiny quality of metals is due to light reflection off the sea of electrons.