For musicals, I would add:
-- Angela Lansbury in Gypsy. For my $$, the single greatest musical performance I have seen.
-- Barbara Harris in The Apple Tree. You had to be there. Pure genius.
-- Patti Lupone in Anything Goes. She did not win the Tony -- she lost to Joanne Gleason in one of the most absurd votes ever...Gleason was very good, but it was not a lead role and Lupone created musical comedy heaven (and I am not a Lupone crazy).
-- Bebe Neuwirth in Chicago. Even superior to Rivera, who was great.
-- Donna Murphy for The King and I. She proved that she had charisma to spare and her voice was even better than re knew.
-- Pearl Bailey in Hello Dolly. I would conjecture that her reviews were even better than Channing's. She was spectacularly good in a larger than life role.
For dramas. I would add:
-- Colleen Dewhurst in Moon for the Misbegotten, for my money the greatest female performance I have seen in a play.
-- Zoe Caldwell in The Prime of Miss Jean Brodie, simply exhilarating. I have not seen the play on 50 years and I remember multiple lines of dialogue from the play, including 'give me a girl of an impressionable age and she is mine for life'. 50+ years.
-- Vanessa Redgrave in LDJIN. I have seen some outstanding Mary Tyrones, but nothing as shattering as hers.
-- Maggie Smith in Lettice and Lovage. Comedic brilliance, staring with the very first scene. She did not win the Tony for Private Lives, but that should be on the list as well
I do not agree with BP for SITPWG. She was excellent, but it was not a 'bestest' (and she did not win, although I recall your saying they did not have to win.
I also remember the acclaim that Donna Murphy received for Passion; I hated the show and thought the gave a one-not. i.e., super intense, performance, which is what was in the script. She gave GREAT performances in The King and I, Wonderful Town and Hello Dolly, so this is not because I don't like her as a performer.