The common bases are...

metal hydroxides such as NaOH, Mg(OH)2 and Al(OH)3

ammonia NH3

metal bicarbonates such as LiHCO3 and Ca(HCO3)2

metal carbonates K2CO3 and BaCO3

What happens when each of these bases reacts with an acid?

metal hydroxides

ammonia

metal bicarbonates and metal carbonates