Gabriel Lorca (Primary)
We know how the story of Gabriel Lorca ends. At least one of them. Lorca was the main villain of the first season of Star Trek: Discovery and was killed off at the end of the season. His ending was unnecessary and had it not been the Mirror Universe version of Lorca, we'd be more upset about his end. Yet, the real Lorca, from the Prime Universe, still exists. Played masterfully by Jason Isaacs, Lorca took fans by storm.
While he wasn't given as much to work with as others, as he only had a few episodes against the full series, it got people excited enough to want to see more of the character. A thing that could very easily happen. Despite Star Trek only having two shows from here on, there are still plenty of opportunities to bring the real Lorca back.
He could arrive in Strange New Worlds, having been saved (or saving) the Enterprise. He could pop up in the future with Starfleet Academy or he could somehow make a return in the Section 31 film (or any of the other films). There are a bunch of ways we can get the real Lorca back and get him back to wrap up a few lingering plot threads.
Like how did he end up missing in the first place?