The Afrikaners have become some of the favorite villains within the realms of alternate history. They've become common enough in their stereotypical role as a bunch of expansionistic racists that they could be considered something of a cliche in the genre. On AH.com, our resident South African member Marius can P-rant extensively on this subject. The 'Afrikaner catchphrase', as coined by Thande's mate Alan, is to lean threateningly across a table and shout “You can't come in here because you're blick!”.
The Domination by S. M. Stirling (novel series). Granted, the Afrikaners themselves comprise only a portion of the Draka stock (along with the slave-holding American loyalists, Hessians, Icelanders, French Royalists, and die-hard Confederates), but the series does end with an evil racist South Africa conquering the world and the Solar System.
The Peshawar Lancers by S. M. Stirling (novel). The Afrikaner captain of the Imperial air yacht assassinates the King-Emperor of the Angrezi Raj, while in the employ of an even more villainous Russian agent. Why did he betray his country to the vile Satanist Russians? Because he was unsatisfied with how nastily the Angrezi treated the blacks in South Africa…
Conquistador by S. M. Stirling (novel). Die-hard members of the AWB are among those recruited by the WASP-friendly Commonwealth of New Virginia as Settlers. Several of the Afrikaners in the book are exact analogues to the miscreants from Turtledove's Guns of the South, though they're even less successful in this universe than in the original GOTS.
As you can see, Steve clearly has a weird fetish for Afrikaner villains.
“The reason I bring up Stirling was that it reminded me of how he views Afrikaners, especially in The Peshawar Lancers where that one Afrikaner airship captain betrays the good guys to the evil Satanist cannibal Russians purely because the British stopped his people from doing some of the nasty things they like doing to 'blicks'. As if Afrikaners literally have nothing more important in life to do then sit up all night thinking of new interesting ways to make black people's lives more hellish.”
In many works on AH.com, there are Afrikaners who are not Afrikaners. User Baconheimer is very into this concept, having created Amerikaners, Amaazoners, and Ostraliaaners in past maps and games. However, his “not-Afrikaners” are generally not evil. The bonus to having Amerikaners is that you can have Theodore Roosevelt as an Amerikaner. Sevarics is currently writing a timeline called “The Rise and Fall of the Amerikaner Republics”. As you can imagine, Amerikaners feature in this timeline alongside a heavily germanized Bohemia.