Here's how I'd describe it: Visuals are a city at night, you can see the colorful lights on buildings. Music loop. Throughout the flash you can select a song to loop, and each song is just a variation/remix of the same song. Some words that may have been in the filename: "mega" "mix" "nights" But can't seem to find it unfortunately. Maybe one of you know it. It also seems like a more modern flash, maybe made after 2013. I personally saw it in 2020, iirc.
The way I found it (sharing my method since it might be useful for others who want to find flash they remember) Remembered that I saw a certain Miku flash at that time. Searched on sfwchan for threads where that Miku flash appeared. Realized it must have been 2019. So browsed 4plebs archive of the date where the Miku flash appeared.
