The best replacement for worlds is oblivion.

The best alternatives to worlds are rated as following:
★★★★★  oblivion
★★★★  bodies
★★  independence day
★★  second life
★★  gurps
★  activision
★  endless space
★  xplor
★  world's
★  two worlds 2
★  copenhagen
★  bodies revealed
★  gothic 3
  bioshock
  batman begins
  dragonfable
  armada 2526
  adventure quest
  star ruler
  one world

Your alternative for worlds is not listed? Suggest!
Speaking about worlds, one probably shouldn't forget about avatars.

Other search terms related to worlds and their ratings are:
★★★★★ avatars
You have in mind a companion for worlds and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of worlds in all years. Click on graph for more.
worlds
oblivion
bodies