Ibn Al-Sunnī records that when ʿĀʾishah – Allāh be pleased with her – wanted to go to sleep she would say:
O Allāh, verily I ask you for good dreams: dreams that are true and not false, beneficial and not harmful.
اللهم إني أسألك رؤيا صالحةً صادقةً غيرَ كاذبةٍ نافعةً غيرَ ضارةٍ
And when she said this, [those who heard her] knew that she would not speak any more until she woke up from the night.
Al-Nawawī, Al-Adhkār ḥadīth 271. Ibn Ḥajr graded it ṣaḥīḥ in Natāʾij Al-Afkār 3:89.