I have 2 cases of precognitive dreams that I know of in my family:
The day after the transparent airplane was invented, my mom had a dream of flying on it. My mom had never had a conversation about invention, as she always remembers discussions about significant inventions, so subconscious memory is ruled out. Similarly, my family has no history of dreaming vividly about new things that aren't yet in society, so confirmation bias is ruled out. I estimate the odds of this being a coincidence at about 10000 to 1.
Yesterday, I had a sleep paralysis episode of an earthquake at about 1:00 AM Pacific time, and at 7:59 PM the same day an earthquake with magnitude 5.1 actually struck within a 50 mile radius of where I lived. It happened almost 5 hours before the first earthquake of magnitude at least 3 struck in California(earthquakes below that are extremely, extremely common(like happen many times daily) and the largest earthquake that happened before the dream was of magnitude 2.8 but was sufficiently far away from me that I definitely wouldn't feel it, the others were at most magnitude 2). Thus, subconscious influence by the environment(aka earthquake happening beforehand) was ruled out. Furthermore, I never have had a nightmare sleep paralysis episode(I've had sleep paralysis many times but this was the first time ever something scary during it happened and when I woke up I was frightened that it might actually be real and it took until I woke up for real to go back to sanity mode), so confirmation bias is ruled out. I searched up the Earthquake history, out of the past 110 years(until the devastating San Franscisco in 1906), 60 earthquakes with magnitude at least 5 happened. Thus, the chance of this being a coincidence is about 650 to 1. These 2 firm cases pretty much establish my conviction that precognitive dreams are real.