Steffi was the second best after Martina Navratilova, or maybe third after Chris in my opinion. She may take 22 grand slam and became golden grand slam in single calendar year. But she was only a single-focused-specialist player, never won any doubles title. And her shine quickly overshadowed two years later by teen age Seles for more than three years, 1990-1993, that time Graf's achievement was poor, only took 2 grand slam meanwhile young and powerful Seles had 8 grand slams, if only the mad fan did not viciously stab Seles at the back, Graf would not as bright as she was and it could be Seles who would come out as the best player. I'm sure about it and I know Graf realize the same thing as well. The proof was that Graf could rise again after the incident, coincidence? I don't think so. In 1995 she had personal problems (her father) but it did not matter at all, Graf still reigned. That's why I could not consider Graf as the best female player, the Seles incident was the only but fatal to her reputation, she no longer had big rival who would stand against her, like Navratilova Vs Evert.
In summary, no archrivalries... no doubles and mixed-doubles... still incomplete.