The rest of the surviving Spartans are trapped in a micro dyson sphere on the planet Reach. Also there is Spartan Grey Team and Spartan Black Team that we done know if they are alive or dead.
There is Kelly,Linda,and Fred trapped in the micro dyson sphere on the planet Onyx. John is floating in the back end of the UNSC frigate Foward unto Dawn towards an unknown planet. Spartan Red Team(Jerome, Douglas, and Alice) are within the UNSC Spirit of Fire somewhere in space. Spartan Black Team which we really dont know much about, they may be dead or alive and there is Spartan Grey Team still out on the front lines somewhere fighting