The McKettrick Series
One of my favorite things about reading is following long standing series by authors. I love the familiarity of seeing the same characters over and over again in each book and seeing how they grow in change. I read a lot of series by my favorite "family" one is the McKettrick Family by Linda Lael Miller.
The series starts the McKettrick ancestors in the days of the Wild West and shows how they settled down and the McKettrick Ranch begin. From there it jumps to the present age where the McKettrick Ranch is now a huge corporation with many interests. It's currently at 15 books and there are also a whole host of the off-relation Creeds as well.
They are kind of grouped in mini trilogies for the most part. My favorite "set" of brothers are Jesse, Rance, and Keegan. It's also the set with the best moment ever when Rance makes it to his daughters birthday party by way of helicopter.
Another set of brothers are Tate, Garrett and Austin. Each family has their own dynamics and "issues" yet they are all a family as well.
One of my favorite things about the McKettricks are the Christmas Series. I love reading about a western Christmas and the writing brings you right back to that time. Historical westerns aren't really my favorite but I have a soft spot for these books.