Project:User access levels

Unregistered IP users

 * See also: Project:Users

Autoconfirmed users

 * See also: Project:Autoconfirmed users

Administrators

 * See also: Project:Administrators

Bureaucrats

 * See also: Project:Bureaucrats

Coders

 * See also: Project:Coder. Somewhat related to the non-user-group Developers.

SVN admins

 * See also: Project:SVN admins.

Stewards

 * See also: Project:Stewards

Importers

 * See also: Project:Importers

Transwiki importers

 * See also: Project:Transwiki importers

Editors

 * See also: Project:Editor. Aka "Reviewers".

Bots

 * See also: Project:Bots

IP block exemptions

 * See also: Project:IP block exemption

Other

 * contestadmin (list)
 * contestant (list)
 * contestjudge (list)
 * translationadmin (list)

Unused user groups
These groups have no members:
 * Accountcreator (list)
 * Autochecked (list)
 * Checkuser (list) (users permitted to use Extension:CheckUser)
 * Confirmed (list)
 * Oversighter (list) (users permitted to use Extension:Oversight and to revision delete revisions from even administrators)

Requesting permissions
Most rights are requested at Project:Requests. Steward rights are handled at meta.wikimedia (stewards).