Well as long as we're talking lists, I may as well put my top 5:
Women
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1. Hilda
2. Manuela
3. Marianne
4. Petra
5. Catherine
Men
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1. Lorenz
2. Alois
3. Claude
4. Raphael
5. Dimitri
This isn't necessarily a list of goodest characters, by the way. For example, I think Lorenz is a terrible person, but he's also a great person at the same time, and that's makes him interesting to me. Similarly with Hilda and Catherine. I think Three Houses on the whole is really good at having dual-layered characters.