Admin HelpersAdmin helper modules are those that provide helpful tools, UI enhancements or optimizations to the admin panel (excluding Fieldtype or Inputfield modules).
AuthenticationModules dealing with logins, passwords, 2-factor authentication, etc.
Core ModulesCore modules are those already included with the ProcessWire core, but not necessarily installed. Most modules listed here can be installed by going to the modules screen and clicking "install" next to the module name.
Development ToolsModules that have more to do with assisting development of a site rather than managing its content.
Email/WireMailModules that work with email as well as modules that implement ProcessWire’s core WireMail type.
Fieldtype ModulesFieldtype modules that represent a data type used by fields.
Import/ExportModules that work with importing or exporting data.
Inputfield ModulesInputfield modules that provide a UI input widget in the ProcessWire admin.
Language ModulesModules involved in providing multi-language support.
Language PacksA full language definition for the ProcessWire admin, used by ProcessWire's Language Support modules.
Logs/MonitoringModules that maintain activity logs or monitor and report activity in some form or another.
Markup GenerationMarkup modules that are called upon to generate or parse markup (like HTML). Markup modules are most often used on the front-end of a site (rather than admin).
Photo/Video/AudioModules that perform some function related to media such as photos and audio/video.
Premium ModulesPremium modules are commercially supported modules available for purchase.
Process ModulesProcess modules are apps that run in the ProcessWire admin.
Proof of ConceptProof of concept modules are designed as examples or starting points for others to build from. May not be ideal for users wanting to plug-n-play.
SEO/AccessibilityModules designed to help site accessibility, standards compliance and SEO.
Site ProfilesA site profile represents a full ProcessWire site ready to be installed.
Social, Feeds, ServicesModules that provide or work with social networking services and/or external feeds.
Textformatter ModulesTextformatter modules that provide run-time formatting for blocks of text (typically used with Text/Textarea fields).
Other ModulesModules that have a unique purpose not covered by existing categories.
Users and AccessModules dealing with access in ProcessWire via Users, Roles or Permissions.