Katharina Dalton (née Kuipers; 1916 – 2004) was a British physician and pioneer in the research of premenstrual stress syndrome (PMS), coining the term, treating many women and testifying as an expert witness in influential court cases. Dalton eventually became the first female president of the general practice section within the Royal Society of Medicine.
Katharina Müller is a German competitive ice dancer. With her skating partner Tim Dieck, she is a two-time German national champion and has won many senior international medals, including two silver medals on the ISU Challenger Series and three gold medals at the German NRW Trophy. They have represented Germany at the European and World championships.
Katharina Klafsky (1855 – 1896) was a Hungarian operatic singer whose acclaimed international career was cut short by a chronic illness which proved fatal.
Katharina of Austria (1533-1572), fifth daughter of Ferdinand I, Holy Roman Emperor. She later married Francesco III Gonzaga, Duke of Mantua and Sigismund II Augustus, King of Poland.
I believe this is one of the (numerous) variants of her name by which Kate is known in Shakespeare's Taming of the Shrew. I'm a Katherine myself, and I kind of like this version of the name, but on the whole I think it's probably more A's than anybody really needs.