As the Genre Turning Point for dramatic television, Babylon 5 focuses heavily on building up a world with quite a bit going on, and the main cast is far, far from alone when it comes to interesting experiences and exploits.
- Centauri Emperor Turhan has spent much of his life seeking to end and atone for his culture's brutal conquest of and subsequent rivalry with the Narn Regime while facing stiff opposition from much of his government and aristocracy. He is also shown both before and after his death to have had an interesting supporting cast of his own throughout his efforts (including his seer wife Morella, a son who died young, Malachi The Good Chancellor, Londo's old friend and fellow Action Politician Urza Jaddo, and Camp Straight longtime courtier Milo Virini).
- Delenn's old mentor Draal is a lifelong do-gooder who shows up during an interplanetary Walking the Earth journey, and ends up performing Man in the Machine duties for the rest of the show (with some help from the Zathras brothers and others of their species), helping the heroes in vital ways several times, while in other episodes, he's so busy with his duties that they can't ask him for help.
- Tessa Halloran spends much of seasons 3 and 4 offscreen as a Rebel Leader on Mars against President Clark (working to avoid civilian casualties and use compartmentalization to avoid the group being betrayed). After Clark's defeat, she struggles to be a political leader of the newly independent Mars amidst bureaucratic red tape and continuing corporate exploitation and, in the penultimate episode, ends up accepting a job running Interstellar Alliance Covert Intelligence to clear out the rot on Mars that way.
- Aldous Gajic from "Grail" is a corporate accountant turned Seeker Archetype who has spent years hunting for the Shrouded in Myth life-regenerating Holy Grail on alien worlds, helping people and picking up self-defense skills along the way. During the episode he recruits an apprentice, Thomas "Jinxo" Jordan, to follow in his footsteps once he is gone.
- Ivanova's father only makes one appearance on his deathbed, but is a renowned author and pacifistic voice who leaves behind a powerful legacy.
- Mr. Reno from "Signs and Portents" is a professional "finder" of long-missing people and objects (including an important Centauri relic Londo is after) who hints at having a great deal of resourcefulness and code of professional conduct that keeps him from ever getting excited no matter what the significance of an object is. However, his ominous comment that You Don't Want to Know how he found the relic could also mean he is the Villain of Another Story during at least some of his searches.
- Walker Smith is a renowned boxer who worked his way to a championship spot from humble origins while being an ally of Garibaldi during his Token Good Cop past. He was framed for doping and disgraced in the sport for refusing to bow to corporate interests, and joins an alien martial arts league in his one appearance while working toward a comeback in boxing.
- Major Krantz from "Babylon Squared" has spent years (although they may have only seemed like weeks from his point of view) trying to maintain order aboard a previous Babylon station with over a thousand people aboard, many of whom are on the verge of nervous breakdowns due to constantly being Unstuck in Time and experiencing bizarre visions (something Krantz himself isn't immune to).
- The unnamed telepath lurker from "Chrysalis" and "A Race Through Dark Places" is an escapee from the unethical Psi Corps Super-Soldier program who has spent a year establishing an Underground Railroad on the steroid for telepaths.
- Techno-Mage Elric from "The Geometry of Shadows" is a wily and powerful Magitek who is savvy about being taken advantage of and is introduced leading his people on an exodus to avoid either side taking advantage of them in the upcoming Vorlon-Shadows war. He ends up starring in a subsequent novel showing his conflicted feelings about the affair and his background, but even in that story, he is already an accomplished member of his order when he first appears, and little is said about his beginnings in the order or his actions throughout the exodus.
- Captain Maynard and the EAS Cortez a huge exploration ship that serve the more traditional Star Trek role of exploration. It's indicated that they spend so much time out exploring, that most EarthForce personnel will be fortunate to see an exploration ship in person once. To hammer the point home, much of Maynard's time spent visiting Babylon 5 had him and Sheridan trading stories about what they'd done over the years since they last met.
- Mariah Cirrus from "The Long Dark" is a former space explorer from a century earlier who had a constant on-off relationship with her fellow explorer and comes out of cryogenic sleep to learn that First Contact happened while she was gone, with her earlier adventures and time adjusting to the new society not getting too much attention.
- Amanda Carter from "Spider in the Web" has spent most of her life trying to get Mars its independence from the Earth Alliance, first as a young activist, then as a diplomat and businessperson after she left behind her old friends for turning to terrorism.
- General Richard Franklin, Dr. Franklin's father is conducting a vital but mostly offscreen campaign during his sole appearance and has nicknames like "Old Firestorm," "The Liberator of the African Bloc," "Hero of the Canal Wars," and "Scourge of Janos VII".
- The Markab have a Never Live It Down reputation for letting themselves get decimated by a plague they wouldn't admit was a problem until it was too late. However, it's notable that many of them, such as Dr. Lazarenn, spend a year working on a cure while trying to move people off of the homeworld in order to combat the contagion without alienating the people they will need to agree to take any cure. Unfortunately, their efforts end in a Nice Job Breaking It, Hero Shoot the Shaggy Dog manner when the plague spreads to most of their colonies and the secretive nature of their research delays important breakthroughs.
- The Markab leaders also seem to be among the first aliens to recognize signs that the Shadows (who they fought against and survived long ago) are returning and are preparing themselves for war against the Shadows before being brought down by the Drafa Plague (with it being speculated in and out of the universe that the Drafa Plague was artificially released to remove them from the playing field).
- Dr. Everett Jacobs from "Hunter, Prey" and Mary Kirkish from "Messages from Earth" are both introduced as people who have spent a while on the run from Clarkâs goons because You Know Too Much, and remain in hiding from him at the end of their episodes.
- When President Clark turns outright dictator in "Point of No Return" and "Severed Dreams", there are plenty of moments showing Clark's opponents outside the main cast. An unseen Action Politician named Senator Borahevsky refuses to abandon her office after Clark disbands the Senate and calls for people to form a human wall around the building to try to make Clark back down. Earth Alliance official General Smit, who implicitly chooses to stay with Clark to try and be an Internal Reformist, sends Sheridan a Public Secret Message that reminds him of how he can resist complying with Clark's orders with some Bothering by the Book. Some brief news footage shows Rebel Leader General Hague and three ships being attacked by a fleet of Clark loyalists but managing to escape (Hague dies offscreen in a subsequent fight, but his men then regroup with Sheridan), causing massive cheering from the people of Babylon Five.
- David "King Arthur" McIntyre, the Shell-Shocked Veteran who lived through the Battle of the Line and much more during the Minbari War and goes on to be a delusional but accomplished and spiritual Knight Errant who eventually leaves to use his knightly methods to help the Narn Resistance.
- In his brief screen time, Centauri Minister of Intelligence Durano comes across as a shrewd, fairly principled, Seen It All spymaster who investigates political murders and other intrigue, chafed at serving the mad Emperor Cartagia and is happy to break free of the restraints the man placed on him as soon as Cartigia is dead. The evidence he uncovered in one of his investigations leads to the downfall of Morden, The Heavy.
- Brother Alwyn from the third flash-forward in "The Deconstruction of Falling Stars" is a Ranger who journeyed to a post-nuclear war Earth, infiltrated the Catholic Church and has spent decades providing relief to needy people while hiding his true origins and recruiting natives of Earth for the Rangers.
- "The Paragon of Animals" features an unnamed Ranger who found a neutral species being menaced by the Raiders, helped the locals fight their oppressors, and was mortally wounded while going to get help.
- By the show's end, races like the Yolu, Abbai, pak'ma'ra, and Drazi have sent Ranger trainees to the Anla'Shok who probably have a whole movie's worth of interesting experiences there but aren't even named.
