It's not only meant to be one, it works much better with just one. More than one just gets crowded and problematic, breaking the action economy of the game.
That said, if they're dead set on the idea as a concept, having non-combative pets might be fun. These would just be trained animals and not subject to the animal companion rules, like if someone bought a horse or dog. Use the Handle Animal skill and give them tricks. And they should stay out of combat.