I was born in '87, so I was barely around for Jem - BUT that doesn't stop me from thinking the show was AWESOME (thanks YouTube)!
Shana Elmsford was the synth drummer - and later guitarist - in Jem's band, The Holograms. She met her bandmates in foster care at Starlight House (the home for girls founded by Jem), which allowed her to come out of her shell, as she was a shy, introverted child. Shana designed most of The Holograms' costumes and breifly left the band to become a full time fashion designer.
Something tells me that she and Friday Foster would definitely get along.
There were other Black Female characters on Jem amongst the Starlight Girls:
Neurotap, Michelle Balters, could be described as the reluctant mutant. She discovered her powers in a most unfortunate way - by putting her mother into a coma. The manifestation of her abilities causes her family extreme distress as well as overwhelming financial burdens. To help pay off her mother's medical bills, Michelle Balters began working at Strong Industries - finding mutants for the villanous Martin Henry Strong to experiment upon - against her better judgement.
Balters' abilities activate when she makes and holds eye contact with an opponent - causing them severe nervous system damage via electric impulses.
Wildstreak appears in the Fantastic Four comics in 1993. Her real name is Tamika Bowden and she wasn't born with any superpowers. She was a gymnast who suffered a severe injury, lost the use of her legs, and then had an exoskeleton built for her that made her strong, faster and even more agile that she had ever been. She began being a vigilante to seek revenge against the mob boss responsible for her accident - because her father, a genius and MIT graduate, refused to work for his organization. WildStreak never conformed to any superhero ethics and was hunted by Iron Man, Super Man, and the Fantastic Four.
Skyrocket's given name is Cecelia Forrestal and she is a scientific genius that created a suit called the Argo Harness which gives her the power to fly, harness untold amounts of energy, and shoot out blast beams. Any attack by fire, radioactivity, heat or electricity is absorbed and makes the suit more powerful. Skyrocket first appeared in the Justice League of America in 2002. Her character has a very interesting history: She was in the Air Force but hit a glass ceiling because of her gender and race so she left and went to work for her parents, the founder of Argo Technologies. Later she worked for the POWER COMPANY to perfect the Argo Harness and use it for good, as many people were tempted to use it's power for evil.
Venus Dee Milo is a Marvel character that first appeared in X-Force in 2001. She has no arms, like the Greek Statue she is named for, Venus de Milo. She discovered her powers during an argument with her parents as a young adult, causing an explosion that destroyed her grandmother's home. She fled depressed and joined the X-Force. Venus is made of pure energy, without the containment suit, made for her by Professor X, she wouldn't have a physical form. She can transport herself from place to place and use her energy as a weapon and to heal herself and others.
SheBang, aka Shenice Vale, is a character on the now defunct Kids' WB show Static Shock. She was engineered by her parents to have superhuman strength and agility. Static Shock was a DC Comic before being animated and has the distinction of not existing in the DC UNIVERSE - meaning that in the context of the Static Shock comic and show, characters like Superman are considered purely fictional - which I think is a pretty cool touch as it adds a sense of realism.
Friction appears in Marvel Comics' DP7. She has the ability to manipulate the surface of objects in her immediate line of vision for up to 250 feet and their natural relationship and attraction to one another - causing things to stick together or become completely frictionless. She uses this power to climb walls and ceilings and quickly glide across flat surfaces. She can also make peoples' body parts adhere... which is just cruel (and pretty awesome in a fight situation). Charlotte was a dancer in college when she discovered her abilities and was admitted into a clinic for the paranormal where she met others with unique talents; the patients soon discovered that the clinic was up to no good and escaped briefly until Charly was captured, returned, and brainwashed. Her story goes on to include racial tensions and riots, the destruction of Pittsburgh in the incident called The Pitt, and CIA employee turned hit-target.
Fatality is no hero; she's actually a supervillain from the DC Comics Universe and sworn enemy of Green Lantern. Green Lantern accidentally destroyed her planet and Fatality was the sole survivor. She came to Earth to exact her revenge but didn't know the identity of Green Lantern, so she tried to kill every Green Lantern she came across. In one of her battles she was presumed dead after her severed arm was found, but no trace of her body was discovered. She resurfaced later with a prosthetic arm attempting to even the score and lost her other arm. She is very skilled in combat and has a mastery of most weapons. She uses a power rod most of the time and a yellow Qwardian ring, which happens to be among the Green Lantern's weaknesses.