Clafrica Cameroonian keyboard available on Google Play and GitHub.
Keyman Keyboards available for 1000+ langauges for Android, iOs, Linux, Mac and Windows devices.
New Kasahorow Android Keyboard for Akan (Fanti, Twi, Akuapem), English, Ga-Dangme, Gbe (Ewe, Ewegbe, Fon), Gĩkũyũ, Hausa, Igbo, Wolof and Yorùbá available on Google Play, F-droid and is also available on GitHub.
SwiftKey for Android available from Google Play.
Gboard for Android available from Google Play.
Yorùbá and Igbo Keyboard for Windows and Mac available from writeyoruba.com.
Amharic on linux can be obtained using ibus. Instructions for Ubuntu here and here. Instructions for other distributions can be found on the ibus wiki.
Amharic soft keyboards include Ethiowebs, GeezLab and Lexilogos.
Freedesktop xkb package includes keyboard layouts for Linux for Akan, Arabic, Botswana, Cameroon, Gĩkũyũ, Hausa, N'Ko, South Africa, Togo, Yorùbá etc. If a keyboard for your language is not available, it is possible to create custom keyboard layouts, for example as described here.
Keyboard for writing in lanugages from Benin, Clavier Fongbe available for on Google Play as a soft keyboard here and on GitHub.
Keycodes for a variety of special characters here.
Taalportaal - online Afrikaans grammar
Kasahorow Afrikaans dictionary
A handbook of the Ateso Language
An Elementary Introduction to the Taita Language
Kamusi ya Kiswahili GitHub GooglePlay
Kasahorow Kiswahili dictionary
Xitsonga English Dictionary at Xitsonga.org