Hi Pedro and welcome to the Forum.
If you want lots of eggs from reliable layers that won't go broody and thus stop laying in mid-season, you would be best to get hybrid layers. There are many varieties of these, all originally produced for commercial set ups where constant egg production is required. They will come fully vaccinated against the main chicken diseases and should be reasonably priced compared with purebreds, which are usually raised in smaller numbers by enthusiasts just because they love the look of the breed.
I have a little Columbian Blacktail, who has been a brilliant layer for nearly two years now, just like the previous CB I had a while before. There are many other kinds, and if you get a mixture of breeds they will each lay a different colour, size and shape of egg, so you can tell who has obliged that day. Just Google Hybrid Hens plus Images and you will get some ideas. Much depends on finding a good breeder or stockist, of course, so you start off with healthy and vigorous girls. If you tell us whereabouts you live, somebody may be able to recommend a good place.
But continual laying does come at a price, all hens are born with all their egg cells in place and once they've used them up, hybrids will stop laying at a younger age than purebreds, who pace themselves better on the whole.
It sounds as if these may be your first hens, am I right? If so, how many were you thinking of getting, and how big a run and coop are you able to offer them? Getting the equipment right is very important as mistakes are expensive to rectify. Lots of help and idea on here, though.