It's commonly believed that at the end of stage shows Allen would reply to George Burns line "Say goodnight, Gracie", with "Goodnight, Gracie". Recordings from the time do not have her using this reply.
Disputed
“Goodnight stars, goodnight air, goodnight noises everywhere.”
Source: Goodnight Moon
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Margaret Wise Brown 9
American children's writer and editor 1910–1952Related quotes

Closing remark to the Presidential debate with Mariano Rajoy in the 2008 election campaign.
As President, 2008

“Goodnight Mrs. Calabash, wherever you are.”
Famous sign-off line to all his radio and TV shows, the meaning of which he never publicly revealed, leading to much speculation and many theories. Only after his death did it become public knowledge that it was reference to his first wife, Jeanne Olson, who died in 1943, and that Calabash was a private name between them for Calabasas, California, where she spent much of the final years of her life.

“(Typical signoff) Goodnight, and have a pleasant tomorrow.”

2000s, Democratic National Convention speech (2008)

“Everyone winds up kissing the wrong person goodnight.”
Variant: Everybody winds up kissing the wrong person goodnight.

“Let it die. Let there be a new beginning. It’s awful. Goodnight.”