The main ones are these two, available in most of the larger South African libraries. The second is the more up to date. Always be aware that these are not infallible - they have only been put together by human beings and inevitably contain mistakes and errors. Use them as a guide, not a source.
South African Genealogies,
A good number of other books have been published over the years which may (or may not!) be found in South African libraries. You can find a list of some here ... but we are unable to provide locations for these. You will have to find them for yourself!