Floor 55 can only be accessed by going to every other floor number that ends with a 5 from 5 up to 55 on elevator number 5. This floor is the Magical Weapons R&D. They test out many different magic weapons in this area, as well as make them. Sometimes they create good weapons (like piles that can cut through anything), and sometimes they don’t (swords that smell awful).

Also secretly the Half-Orc receptionist denies any existence of floor 55

Floor 56 is a potato

Floor 57 is completely overfilled with Mothmen awaiting the next prey.

58 is a kraken's brain.

Floor 59 is there to warp the people out of this Planet ( to any random spot of the Universe ).

Floor 60 is Youtube.  Every wall has at least 30 screens on them, each playing a different episode of Critical Role/Vox Machina

Floor 61 it's empty of furniture. Only there's a cocoon on a nest.

Floor 62 is debating what the point of its continued existence is. And likes marmalade.

Floor 63 is only reachable by using the secret 7th elevator and going to floor 9. When you press the button for 9, it takes you up to floor 63. This is an alien testing lab. People hurry about, performing different tests on aliens. When you step out of the elevator, someone hurried over an injects you with a syringe. You wake up in a room that looks like a jail cell. There is a bathroom with a mirror, and when you look in it, you see an alien. You are doomed to stay here forever.

Floor 64 is the lair of Kaleral the Vile, Scion of Orcus, Master of Undeath.

Floor 65 it's filled with echoes of the present past.

Floor 66 is filled with Amazon Echos, from ages past. 

Floor 67 is accessible only by spinning around exactly 67 times in each of the 6 elevators on the first floor. Contained on this floor, is a portal to each and every floor that is a prime number.

Floor 69 can only be reached by bringing a weapon upon entry. A magical portal then opens up, which takes you to an arena where a massive battle royale is happening. The cool thing about this particular battle royale is, when you die, you automatically respawn, so it's basically an infinite battle. An aasimar greets you and tells you the rules before you can enter. He is about to finish, "But most importantly, have fun-" before he gets impaled by a spear. The only way out of this floor is through Floor 70.

Floor 68 is the plane of Apollo. Music is blasting everywhere, poetry is being performed, and prophecies are being predicted. It is only accessed by getting on elevator 6, pressing the button 8, and singing the chorus to “Different World” (by Alan Walker, K-391, and Sofia Carson, feet. CORSAK) out loud. (I miss when people were so much more creative with their floors. Just compare what is here (excluding me) and what there was at the beginning)

Floor 69 is filled with... errrrrrrrrrrrr....... ( I think I gonna be banned if I tell the EXPLICIT theme here )

Floor 70.0 is James Bonds' base.

floor 71 is a flooded room

Floor 72 is the Penthouse and Rooftop bar. (You have reached the top of the building).