>>37431560You'd probably see the same thing the anime might sometimes show off: working men and women with their Pokemon to help them, like construction workers with Machoke and Conkeldurr, police with pretty much anything resembling a canine like Growlithe or Houndoom, etc.
In the context of regular household pets and companions you probably won't see many exotic choices on account of their special needs, like Magnemite needing a constant electrical supply or pretty much any Ghost that needs life energy or emotions to be fed. In fact I'm willing to bet most Ghosts that aren't outright predatory would be considered pests and you'd need to call an exterminator to get rid of a Ghastly infestation or to shoo away flocks of Lampent from hospitals.