A scenario I always have in my head is Loric and Loric-related ghosts following around the survivors after the series and watching them continue their lives.
Sarah and Henri watching from aside as John builds new Lorien, breaking down several times in the process. Sarah tries to hug him knowing he doesn't feel her at all.
Eight being around every time Marina cries over him. It hurts to watch her being so unable to let go, but he stays there, smiling, consoling her, hoping she would forgive herself one day.
Katarina would be so proud of Six. She's one of the few ghosts who aren't constantly troubled think of those they left behind, despite the bittersweetness of not being able to be there.
Crayton is always around the nights that Ella can't sleep from the nightmares. He's there on the nights she sleeps too.
One, Maggie and Hannu took a long time to get over how much they'd missed on for being the first ones. But none of them regret it when they look at what the others accomplished. It hurt, sometimes. Being remembered as a concept rather than a person. And when it feels that way, they always have their graves to go back to.
Five spent a lot of his days right in the cell with Einar, hesitating to sooth or 'touch' him every time he whimpers from the shocks of the Inhibitor. He could only hope the human Garde would get the chance start anew one day, the same chance Einar gave him.
Ran alternates between her friends, but the wound is still too fresh not to hurt when they're talking and sometimes having fun she couldn't share with them. She's always tracing the scar on Nigel's face when he's sitting there blankly, and probably thinking of his best friend.