Here is the 1957 Beethoven third concerto with Gould, Karajan, and the Berlin Philharmonic, a very lyrical performance.
https://www.youtube.com/watch?v=0-dwTWlD9xo
Karajan also accompanied Gould in 1958 and 1959 with the Bach d minor concerto, with both the Berlin Philharmonic and the Philharmonia orchestras.
Karajan's reaction to Gould's Beethoven:
"This Beethoven concerto performance was a masterly achievement that very few artists will duplicate in our lifetime. When I heard Gould play, I felt as if I was playing myself, for his performance was exactly in line with my own view of the music."
Karajan offered to accompany and launch Gould in every city that Karajan conducted in.
Bernstein called Gould "the greatest thing to happen to classical music in recent years", and performed frequently with him from January, 1957 to April, 1962.
Bernstein wanted to continue the partnership, but Gould was withdrawing from live performance.
Karajan and Bernstein did not make such offers to Backhaus, Kempff, Gulda, Brendel or Kissin.