DIMENSION MOD IDEA!!!! PLEASE!

an underwater dimension with cool mobs dungeons and large "atlantis" type buildings

What about a nightmare dimension? Its like the overworld, but its night the whole time and grass, leaves, ... are much darker and have got a deep blue color. The mobs in the dimension are a lot of different ghosts and demons. structurs could be different ghost houses with different bosses like bigger ghost, devils, ... if you beat them, you'll get some cool stuff! like diamonds. The portal could be made with netherrack but you decide.

JA how about this. Floating islands (Chutlu_follower) in which the tribes each worship a sacred element. Now there are the two overlord tribes... sun and moon lord or something like that. make tools and stuff and make the npc have able to waterbend or fire bend or... o cool it can be sorta like avatar. whatever anyways seems like a good idea. There will be like different trees and ores and stuff, but each region has its own sacred treasure which is and powerful weapon like a fire stick or a water staff and stuff, sorta like equivalent exchange. Sun and moon weapons awesome of course. regions include- earth, water,air, fire, war nomads, archers, and (sun spirit and moon lord). of course list could be added onto. there good idea i think. credit sounds nice ;/

How about this idea...
The Past World(or something like that)
A dimension in which the past world takes place where steve and all the other humans(or minecraftians) used to live. Such as destroyed building or corroded cities and here is technically a back story if you don't understand...

Steve used to live in a metropolis, filled with people and activities, until the end of the world would come... and since steve was a great scientist, he and some other scientist built a "Time Portal" and its supposed to bring you to the age right after the "burning age", the age right after the end of the world, and the age right after that is the "reformation age", an age where grass grows, animals roam, and water flows. So that's the age Steve will live because he's the first one to enter before the portal shuts down...

So maybe a portal back to that dimension(NOTE: This a dimension not another TIME PORTAL so it will not bring you to cities with people roaming freely and also that time is considered to be like another dimension sort of so time portal and the dimension portal are compatible with each other)

Think about if you'd like, if it sounds to hard its fine because its just an idea,

a dimension that is like a paradise with loads of valuabels! (but you need diamond loads of diamond blocks to get there so it's pretty end game)

What about a dimension of differences with floatig islands linked up with bridges some of with tribes in war with each other and lots of different ores,vilages,temples and stuff like that(new trees).