in some of the Halo games, you work alone until you find Cortana your ai companion
in the division, you work alone going through missions to figure out who the rogue agents and big bad are
in Borderlands 1 and 2, you work alone in a majority of the missions killing different bosses and enemies
in destiny 1 and 2 you work alone going through different missions on different planets
in season 2 episode 1 the flash works alone after abandoning his team. After what happened in season 1 episode 23.
in season 1 Oliver Queen works alone as the arrow defending the city from corrupted people