Finding an outdoor dog is easy as the majority of breeds are made to be outdoors, but finding a good indoor dog is much more difficult. The good news is that while there may not be total agreement among experts on which dogs are best suited for the indoors, this is because there are so many good dog breeds who can make excellent inside house pets.
The Pekingese might not be the first breed that jumps to mind, but these dogs are friendly, loyal, playful without having too much energy and extremely heat sensitive. In fact, it almost seems like they were made for indoors, as they cannot handle hot weather and do best in air conditioned environments in the summer. The Pekingese breed is also best suited to sleep inside instead of out, which automatically seems to make it an inside dog.
The basset hound is known for its good temper, and while these dogs need daily exercise, it does not have to be strenuous exercise. A short 15-minute walk or just 15 minutes of playing inside should be enough to tide these guys over. Maybe even better for those people who want an indoor dog is that while the basset hound requires daily exercise, their preferred activity for the day is finding a comfortable spot to lie down and relax. This laid back nature makes it easy to adjust to indoor life as they do not have excess energy to burn off all the time.
The English bulldog is a breed that does very well indoors. These dogs tend to be very loyal, and are known for being good with children. They have a reputation for being "characters" as they've been known to snort, snore, and be outright stubborn. But stubborn doesn't equal mean, and with a minimal amount of exercise they tend to be very happy and are generally fairly docile. They are very tolerant and don't get excited easily, making them a fairly good choice as an indoor dog for a family with kids.