Part of a high level dungeon I created, loosely base don the same tower from Final Fantasy 1. The tower was created by the gods to test & forge people into heroes, being granted legendary weapons at the top. As such, each floor is basically it's own pocket dimension with it's own rules & types of enemies, and there is often powerful magic that can hinder or restrict the players. Each tier is meant to take one adventuring day, with 2 short rests and a long rest.

Tier 2 covers floors 6-10. Here are the notes, rules, & themes intend for each floor.

F6: Rest, there is no map, no need for it. It was big room that magically had whatever they wanted for downtime to take a long rest.
F7: Water, entire floor is underwater (players had magic items that let them move & breath normally underwater). The floor can be seen completely, no walls, instead the floor is housed in almost bubbles, they can swim outside the walls to move to different rooms. Water creatures can attack from the darkened waters outside of the rooms.
F8: Metal, a type of clockwork floor filled with constructs & clockwork creatures. No special rules, more standard dungeon.
F9: Darkness, standard cave dungeon but filled with magical darkness rendering Darkvision useless, players have to rely on light sources, those sources only extend out to 15ft. Filled with dark & undead creatures.
F10: space, a very unique floor taking place in space. The walkways & rooms are made up of light, no walls but there are invisible walls that separate the rooms & can't be crossed no matter how high they fly. The floor is warped, making it difficult to percieve, and different floors have different gravity, so a room can look like a wall far away, and the hallway leading to it bends gravity so the players basically start walking up a wall like spiderman. Filled with space like creatures, they can enter & leave rooms at will, ignoring the invisible walls. Players in my campaign fought an Ancient Void Dragon here as the last boss of the day, floor 11 is a rest floor.