The levels of the backrooms that I’ve personally been to myself (in my dreams that is).

Level 3999, level -18, level -33, level 48, level 37, crimson forest (or just about any forested level without anything harmful in it for that matter), level 6.1 and level 11 (or again any city or town without anything harmful in it for that matter). levels 32 and 303 and 1339 and any other amusement park level. Level 1326 and level 46. Level 0, level 5 and level 8. Level “The End” otherwise known as the “Infinite Library” and level 3 (the prison version of it anyways). Level 735; Levels 8999 and any other levels having to do with malls and very large shopping centers filled to the brim with evil mannequins. Any and all of the levels having to do with seemingly never-ending slides that usually lead to levels such as level 8999 and any other levels having to do with malls and very large shopping centers filled to the brim with evil mannequins. The never ending staircase levels 112 and 9223372036854775807; The infinity mirrors level 308 where you are trapped in rooms created solely out of mirrors all facing each other forever.