The more I think about it I can't think of very many Pokémon games that don't have a cool feature that you need either internet or other nearby players for. The Festival Plaza in Alola, Secret Bases in Hoenn, random people and Pokémon helping you with O-powers and Pokémon Amie as well as the friend safari in Kalos, and going back 15 years (and 3 weeks in the future) there's the Sinnoh Underground. I never figured out the C-Gear and Dream World in Unova, but I eventually realized it would have added a lot.