Orpingtons (of any color, Mt Healthy has a bunch of colors if you want to be able to tell them apart easily), are friendly, docile, and lay a good amount of eggs. Buff is the most common color. Speckled Sussex are another great gentle breed, and they are generally a bit smaller than Orpingtons. Easter Eggers and Ameraucanas are also usually tiny & gentle, and would give you blue or green eggs. I also really like Australorps, they are great layers and gentle, and Mt Healthy also has a few colors of that breed as well. Black is most common. You could get 2 of a couple breeds so everyone has a buddy, and have a little variety in your flock if that’s your thing!
If you aren’t concerned with friendly & gentle, leghorns are by far the best layers.