Hey . Honestly not sure exactly what you mean by "common" but if you mean not a rare breed. Sex links are the best egg layers from what I hear(I actually have all heritage breed chickens and mine are good consistent layers as well). But sex links are fairly common in that almost all the feed stores that carry chicks this time of year have some type of sex link breed(Golden Comet, Black or Red Star etc.) Good luck in your search for prolific egg layers
Red and black sex links, ISA browns, golden comets, white leghorns, black australorps and rhode island reds. All available all over the place, cheap, lay 250+ eggs a year depending on environment.
More heritage/dual purpose wise you could look at plymouth rocks (especially white and barred), wyandottes, orpingtons, brahmas or any number of other birds for a slight reduction in egg laying but more color in your flock.