Israfel
Scholars have said that if a dreamer sees the Angel Israfel (PBUH) saddened while blowing the trumpet, and believes they alone heard the sound, it may indicate the dreamer's impending death. If they believe everyone in that place heard it, it might suggest a widespread deadly epidemic in that area. It was also said that this vision could indicate the establishment of justice after the spread of injustice and the destruction of oppressors in that region.
Per Ibn Sirin's Muntakhab al-Kalam fi Tafsir al-Ahlam