I use a few… mostly custom careers from Kiarasims and Midnitetech to fill in gaps of jobs that I don’t think the game covers, for example real estate agent, graphic designer, construction worker, model, airline pilot, or firefighter. After playing the same careers over and over in a multi-generation rotational file, it’s nice to add a bit more variety to career choices.
P.S. I highly recommend both of these modders’ careers. They’re well done, well written, fit seemlessly into the game, and in some ways add a bit more challenge than the maxis careers.