Terraria – Can’t find world and player folders in terraria folder

Pretty much all of the biomes (using Terraria's liberal definition of "biome") can be moved to another location, within certain limits.

The most extreme example is a Meteor crash site biome, which can exist anywhere, at any height. At the other end of the spectrum, we have the Dungeon, which cannot be moved at all.

Completely immovable

• The Dungeon, because it requires an unsafe background wall below the Dirt Wall depth (cannot be placed by the player).
• The Underworld, which is restricted to the very bottom of the map
• The Sky, which, like the Underworld, is just there at a certain altitude.

Mostly immovable

• The Ocean is not completely immovable, but very inflexible. It is both restricted to a certain height (above the surface level), and can only exist within 250 blocks from either edge of the map. You can create an artificial Ocean in the middle of the map, but that won't spawn Sharks, nor will it grow Corals. Creating artificial Oceans that sort of float above the real one does work; I have actually done so to farm Corals.

There is no character number. Terraria just loads all .plr files in its player save directory, in no particular order.

If you copied over a player file and the character isn't showing up, then it's either corrupted or you didn't do it right. Also, there is a hardcoded limit of 5 characters, so if you're already at that limit, there's your problem.