The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- File management templates (1 member)
- Flag templates (1 member)
- Formatting templates (23 members)
- French armed forces (0 members)
- George Curzon (3 members)
- George V (1 member)
- German armed forces (0 members)
- Glossary (2 members)
- Glossary of words and phrases (1,301 members)
- Glossary templates (3 members)
- Great Britain (1 member)
- Great Speeches of the War (14 members)
- Great War Index (567 members)
- Great War events by day (344 members)
- Great War events by month (12 members)
- Great War events by year (5 members)
- Great War events in April (30 members)
- Great War events in August (31 members)
- Great War events in December (31 members)
- Great War events in February (28 members)
- Great War events in January (31 members)
- Great War events in July (31 members)
- Great War events in June (30 members)
- Great War events in March (31 members)
- Great War events in May (10 members)
- Great War events in November (30 members)
- Great War events in October (31 members)
- Great War events in September (30 members)
- Header templates (2 members)
- Herbert Henry Asquith (4 members)
- Herbert Kitchener, 1st Earl Kitchener (1 member)
- Hidden categories (1 member)
- Images by licence (3 members)
- Images from the Imperial War Museum (8 members)
- Images of the Great War (6 members)
- Images used for site administration (9 members)
- Images used for site projects (1 member)
- Imperial War Museums (1 member)
- Index of Australian ships (1 member)
- Index of German ships (21 members)
- Index of Italian ships (1 member)
- Index of Ottoman ships (1 member)
- Index of Russian ships (1 member)
- Index of United Kingdom ships (25 members)
- Index of battles (4 members)
- Index of lakes (1 member)
- Index of people (51 members)
- Index of places (424 members)
- Index of political events (3 members)
- Index of rivers (22 members)