On GitHub I can find several Mathematica packages working with either quaternions or octonions. But none that covers both, the hyper complex numbers.
https://github.com/search?q=Quaternions%20language%3AMathematica&type=repositories
https://github.com/search?q=Octonions%20language%3AMathematica&type=repositories
https://github.com/search?q=Hypercomplex%20language%3AMathematica&type=repositories
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