According to SyfyWire
There are 8 tribes.
- The Panther Tribe: The Royal Family
King T’Challa (Chadwick Boseman), his stepsister Princess Shuri (Letitia Wright) and her mother, the King’s stepmother Queen Mother Ramonda (Angela Bassett) currently rule Wakanda. The royal family is protected by the Dora Milaje, Wakanda's Royal Guard headed by General Okoye (Danai Gurira) and her First in Command Ayo (Florence Kasumba).
- War Dogs
The family may have the Dora Milaje, but the country has protection as well in the form of the Wakandan Secret police, called Hatut Zeraze (The Dogs of War). In the comics the War Dogs are confined to Wakanda, only traveling with the King when necessary. In director Ryan Coogler’s MCU version, they are stationed all over the world and keep an eye on political unrest and other vital information, then report back to the Wakandan Empire.Usually, they just observe, but Nakiya (Lupita Nyong’o) is a War Dog and is stationed in what appears to be Nigeria on a mission to rescue girls from a Boko Haram-type situation when we first meet her. She also travels with T’Challa and Okoye to track down Klaue. All War Dogs are identified by a tattoo inside their lower lip of Wakandan glyphs.
- Border Tribe ("the Rhino guys")
Also providing Wakanda protection is the Border Tribe, who appropriately enough protects Wakanda’s borders. From the air they appear as simple cattle herders in the lower mountains of Wakanda, their brightly colored Lesotho blankets to keeping them warm. However, the blankets conceal all of their weaponry and the Vibranium woven into them makes the fabric double as shields. They also raise Battle Rhinos.
Always gearing Royal Purple, the Priests, led by Zuri (Forest Whitaker) are the sole caretakers of the temple and all royal rituals in the kingdom. They are herbalists, and botanists and the sole caretakers of the heart-shaped herb that gives the Black Panther King his powers.
- Mining Tribe
The Mining Tribe is solely responsible for the Mining of Vibranium in Wakanda. Being that the ore is Wakanda’s most precious resource, the Mining Tribe is pretty powerful.
- River Tribe
In the movie, the River Tribe has dominion over the water ways. During the Warrior Falls scene, we see Nakiya dancing and her father praising what might possibly be a water deity. Since the Panther’s ritual battle takes place on the water it would be in line with most African traditions to bless the water before one enters it.
- Merchant Tribe
The merchant tribe is over the commerce and trade within Wakanda and is basically over the economic stability of the country. The Merchant Tribe elder also has a seat in the King T'challa's court.
- The Jabari
The Jabari separated themselves and continue practicing the “old” Wakandan ways without technology. They live in the mountains of Wakanda and worship the White Ape deity. M’baku is their leader and in the comics was considered as powerful as T’Challa, even without the heart-shape herb.
"Why did they not help?"
It might be due to several reasons instead of 1. You need to remember that Wakanda is very large and one of the reasons they might not have come to help is because they might not have known about the fight that's going on. As far as everyone is concerned (at the point)
T'Challa is dead.
Only the Jabari and the Royal Guards who seen him in the flesh know he is still alive.
Also the Jabari originally refused to help because he did not want to risk his men's life to take back the Throne especially when" no King has been up here [Jabari Lands] for years"
Meaning most past Kings didn't really care about the Jabari. T'Challa managed to convince him to help. The other tribes might feel the same way thinking it's not worth risking their peoples lives to save a King that Killmonger said 'wasn't strong enough' to protect his people.
Also the other tribes aren't allowed to just go against their King orders like the Royal Guards did. The Royal Guards found a loophole stating that
Technically T'Challa didn't die therefore the challenge to the death is still on
You must also consider that these other tribes aren't actually warrior tribes as well. The Priest tribe only look after the Heart Shaped Herbs and don't fight and the Merchants only sell their armies wont be powerful enough to combat the Border Tribe and Killmonger's Black Panther suit.
The Jabari tribe however separated themselves and stuck to old Wakandan traditions so they have their own army, they are like a country within a country. They isolated themselves from the rest of Wakanda making their own army and their own resources. They actually have warriors to fight and therefore can actually help T'Challa.