ActiveWorlds explore or create virtual worlds
AvaCon create an account and an avatar to visit this private grid for conferences and other educational events
EVE Online  "a massive multiplayer online roleplaying space game"
Hyperica  Directory of hypergrid destinations
Immerse Learning  a fee-based software download for a closed environment; launched Feb. 2014
Inworldz ; closed as of 2019
Kitely  explore virtual worlds or create your own virtual world
Minecraft  "a game about breaking and placing blocks"
OpenSim  "an open source multi-platform, multi-user 3D application server. It can be used to create a virtual environment (or world)"
Open Wonderland  build your own virtual world using an open source java-based toolkit
The Sims 
Tomodachi Life  virtual world via Nintendo device
- Selected list of blogs about virtual worlds:
Bryn Oh the blog of a virtual artist
jokaydia virtual worlds and games for learning
New World Notes James Wagner Au continues to report from the metaverse
SL Enquirer news source for events happening in Second Life
Virtual Outworlding blog written by Selby Evans/Thinkerer Melville covers virtual worlds events, news and other important developments in virtual worlds and the hypergrid
A List of magazines published in virtual worlds or published on the web
Rez Magazine SL arts and life magazine