Bukkit

The multiworld plugin made by ferrybig

Creates cleanroom-style flat world generator with fully customizable layers. It can also be used to create empty space maps!

Pre-generates chunks, quickly, efficiently, and safely

A Skyblock Plugin

PlotSquared

Nothing but void!

This plugin allow full control of normal world generator

Exotic Garden

Provides automated plots with protection (MultiWorld support)

for use with InfinitePlots and WorldGuard, creates regions automatically for new players

A plugin for Bukkit based Minecraft server that adds a floating island dimension similar to the old skylands.

An epic Minecraft Bukkit world generator

MagicLoot

CityWorld

IslandWorld - Survive on small isle

Creates Hunger Games styled arenas and gameplay

Giant Caves is a bukkit mod that creates giant underground caves in the world.

A simple void world generator.

uSkyBlock

Sewers