The "thumb-piano", unique to Africa and widely distributed, is most popularly known as the mbira but also gets called marimba, kalimba, likembe, sansa etc - it has a variety of manuals, key-tunings & types of resonators, which are all documented and explained here -

Alur - Binza - Gogo - Karanga - Lala - Luba - Medje - Mbunda - Ndau - Njanj - Nyamwezi - Nyoro - Soga - Venda