Well, I promised foes of the Lor Republic before, but I decided I wanted to do this instead. Mainly cause it will partially come into play in Yeo's next campaign and a bit in mine.
Because the world of Dragonball Z is so different from the main crinoverse, it will take a great deal more differences: So lets get started.
Son Goku: A hero of the silver age and a founding member of the Tokyo Defense League, Goku is a member of the Saiyan race, an alien race that was largely wiped out by the Planet Trade years ago. When he landed on Earth, Kakkarott was found by Son Gohan, a monk of the White Lotus, who took him in and raised him. Thanks to a bump on the head, Goku forgot about his saiyan programming and became a good natured, if somewhat dim, hero. A powerful martial artist, Goku mastered numerous martial arts, and was a mainstay of the Tokyo Defense League. Goku met his final end during the fateful battle with Tetsuo. Goku was strong, but no match for Tetsuo's psychic powers. Unlike the Goku of other worlds, He never discovered his alien heritage and never became a super Saiyan.
Great Saiyaman: The son of Goku, Gohan is a half Saiyan and super powerful, even moreso than his dad. A member of the Tokyo Defense league, Gohan DID eventually become a Super Saiyan during the battle with Majin Buu years ago.
Yamcha: One of Goku's old friends, Yamcha is a bandit turned White Lotus member.
Krillen: Another White Lotus Member, Krillen is a powerful martial artist and one of the most powerful fighters on Earth. Another old friend of Goku.
Master Roshi: An elderly and perverted martial arts master. Roshi was a mentor to Goku.
Tien and Chaotsu: Former agents of the Black Hand, Chaotsu is a Jiang Shi, and Tien a mystically created mutant. They eventually defected to the White Lotus.
Piccolo: The son of Goku's old enemy King Piccolo, Piccolo was Goku's rival, but they became friends following a battle with Garlic Jr. And became a mentor to Gohan.
Kami: An ancient Namkeian who came to Earth years ago, Kami is one of the elder members of the White Lotus society.
Mr. Popo: A member of the Djinn race bound to serve the White Lotus society, he is no less evil and terrifying, but is largely bound to use his powers for good.
Yajirobe: One of the deadliest swordsmen on the planet. Yajirobe is nevertheless a fat, lazy slob.
Videl: Gohan's wife, Videl is the daughter of Mr. Satan, a pro wrestler turned low end hero and glory hound. Videl has trained in Kaio Ken and is the only current warrior who knows how to use the fabled Spirit Bomb. She also wields the fabled Z sword, making her nearly on par with her husband.
Goten: In this universe, Goten is not Gohan's brother, but his elder son. Goten can also go super Saiyan.
Pan: Gohan and Videl's daughter, she can not yet go super saiyan, but is strong and has her grandfather's extending staff and Nimbus cloud.
Bulma: A childhood friend of Goku, Bulma is the head of Capsule corp, a Japanese company which pioneered technology that allows the compression of tech to tiny capsules. Wife to Yamcha.
Trunks: Son of Bulma and Yamcha, when Trunks was a baby he was kidnapped by Goku's old enemy Dr. Wheelo, who grafted Saiyan DNA to his body, making him a half Saiyan. He can turn into a super saiyan, and is best friend to Goten.
Enemies of DBZ
The Saiyans: there are a small handful of Saiyans left: Bardock and his team managed to escape the slaughter of Frieza, as well as his son Radditz, the exiled prince Tarble, Paragus, and his son the legendary Super Saiyan Brolli. They are currently seeking out other surviving Saiyans to join them against Frieza.
The Planet Trade Menaces to the Lor Repubic and other groups, the Planet Trade are an army of powerful soldiers who wipe out entire worlds to sell to unscrupulous buyers. They are led by the nefarious King Cold and his sons, Cooler and Frieza.
Majin Buu: An ancient demon created by the evil wizard Bibidi, Buu wiped out numerous galaxies before he was beaten and sealed away on Earth. Freed by the wizard Babidi, he was defeated by a small army of super heroes and sealed in the Cooler. He escaped, and is still at large. Buu is powerful, but simple and childlike, with a sweet tooth.
The Red Ribbon Army: A terrorist organization during the Silver Age, they were wiped out by Goku, they are survived by Dr. Gero, who has built a small army of androids and cyborgs to bedevil Gohan and his family and friends.
Garlic Jr.: A native to the planet Makyo, Garlic Jr. became immortal by way of the Dragonballs, and has menaced Goku and Gohan several times, each time being banished to the dreaded dead zone.
Dr. Wheelo: A mad scientist who lost his body and became a brain in a jar, Wheelo sought to steal Goku's body for his own. Using countless bioengineered monsters to menace him.
Turles: A Saiyan warrior and Pirate, he and his band are currently seeking a world to plant the tree of might upon, a deadly super plant which will kill any world it is planted upon.
Lord Slug: A rogue Namekian, Lord Slug traveled from world to world to destroy them. He met his end at the hands of the Avengers when he tried to conquer Xeron.
Bojack: A mutated Vhanian pirate, Bojack and his crew are rival pirates to the Dimensional Pirate Fandango. Unlike Fandango, who is a dashing rogue, and Barbados Slim, who is a smug braggart, Bojack is a murderous monster and butcher.
Janemba: A member of the Pantheon of Discord, Janemba is the lord of absurdity; An all powerful idiot created by a freak accident in the afterlife, with the power to radically alter the rules of life and death throughout the multiverse. Janemba has visited Earth 409 before, and has been driven off by Adrian Eldrich.
Hirudegarn: A huge demon, Hirudegarn was created by the Kashvar, a race of bigoted dark mages who seek to wipe out all "lesser" races from "their" universe. He was sealed away eons ago, but the last of the Kashvar, Hoi, seeks a way to free it.
Anyways, I know that's not an exhaustive list. Anyone want to see anything added, feel free to ask.