2. Din Djarin/The Mandalorian
Seeing as The Mandalorian is currently the flagship series on Disney+, it would make a lot of sense for the showrunners to try and include its protagonist in some way.
Following the season finale of The Mandalorian, the future of the titular character, Din Djarin, is currently up in the air, so bringing him into The Book of Boba Fett could be a nice way to continue his story.
Throughout the first two seasons of his show. Din’s story arc has been that of protecting the Child (Grogu) and delivering him to a Jedi to be properly trained in the ways of the Force. Now that he has fulfilled his mission, what comes next for Din remains unknown.
One likely path for him is to join Bo-Katan in her quest to reclaim the planet Mandalore, as he is the new owner of the Darksaber, but another is that he may try to return to his old ways as a bounty hunter.
Prior to the events of the show, Djarin was a skilled bounty hunter. And seeing as he appeared to be uninterested in having anything to do with Mandalore, traveling the galaxy collecting bounties may be his first option following the end of his mission with Grogu.
However, without his old covert of Mandalorians and without a ship to travel in, he’d likely need help getting started again. Seeing as his old contact Boba Fett has taken over as a crime lord of Tatooine, he may turn to Fett for assistance.