The ones listed below are the ones I thought were the most interesting or credible.
I did skip a few legendary creatures that have now been identified. In the 1700s and 1800s much of Africa was unexplored by people who published in the English language news and journals. I found several sites that says the Bili or Bondo apes of the Congo have been identified.
They are described by natives to the area as being lion-eating. I saw one reference that said explorers have seen that.
Four years ago, Hicks and a team of scientists set up motion detecting cameras and finally managed to capture clear images of the Bili apes. DNA tests, meanwhile, confirmed that the apes were in fact chimpanzees, not a new species. The mystery had finally been solved, but Hicks’ first-hand observations showed that these chimps displayed some very unique behavior.
“They have a different diet, different culture,” Hicks says. “They often nest on the ground, like gorillas do and they use the longest tools we have seen in Africa to dip for ants or honey.”
quoted from NBCNews
THE STILL LEGENDARY CREATURES OF THE AFRICAN CONTINENT
Kongamato of Zambia, Angola, and Congo:
explorer Frank Welland described it in his 1932 book In Witchbound Africa. The Kongamato (“overwhelmer of boats”), is described as a large, reddish creature with leathery wings, devoid of feathers. Eyewitnesses who are shown an illustration of the pterodactyl unanimously agreed to this identification of the Kongamato. “The evidence for the pterodactyl is that the natives can describe it so accurately, unprompted, and that they all agree about it. There is negative support also in the fact that they said they could not identify any other of the prehistoric monsters which I showed them…The natives do not consider it to be an unnatural thing like a mulombe [demon] only a very awful thing, like a man-eating lion or a rogue elephant, but infinitely worse… I have mentioned the Jiundu swamp [northwestern Zambia] as one of the reputed haunts of the kongamato, and I must say that the place itself is the very kind of place in which such a reptile might exist, if it is possible anywhere.” (Welland, 1932, pp. 238, 240.)
quoted from here
Gbahali of Liberia:
The Gbahali is a reptilian creature of Liberia, resembling a crocodile. It grows to 30 feet long, has a snout shorter than a croc’s, and somewhat longer legs. Although this species is not confirmed by science, it is not considered a legendary monster among Liberian hunters, but a real creature they have caught and eaten. It is possible, however, that descriptions are exaggerated. Witnesses were shown a picture of the extinct animal Postosuchus, and they recognized it as the Gbahali.
quoted from MentalFloss
Ninki Nanka of Gambia:
[T]he local name for the Gambian river and swamp monster is Ninki Nanka, which roughly translate as Dragon-Devil. It’s reputed to live along the Gambia River and in the uninhabited mangrove swamps and is usually only seen at night, when it is said to emerge from its lair and eat whatever lies in its path!
The size of Ninki Nanka seems to vary greatly depending of which story you read. It is generally though to be around 30 feet (10 meters) long. But there are stories of it being as big as 50 feet long, that’s a whooping 15 meters!
Possibly the most famous description of the creature suggests it has the body of a Crocodile, the neck of a Giraffe and the head of a Horse – with three horns, one one either side and a larger one on top of its head. Although there have been reports suggesting it is like a large snake or even a large lizard, possibly something similar to Komodo dragon.
A 30 foot komodo would be a scary sight…
quoted from Cryptoworld UK
Step aside Europe, with your nasty werewolves! Here in Africa, we have werehyenas. In Ethopia, it is believed that every blacksmith, whose trade is hereditary, is really a wizard or witch that has the power to change into a hyena. These blacksmith werehyenas are believed to rob graves at midnight, and are referred to as bouda.
picture and quote from here