You usually find a collection of reference tables in the back of dictionaries, almanacs, and encyclopedias (or an index of them, if they're scattered throughout the work). As these tables appear in Wikipedia, please add them to this index.
What we have in mind is listings or tabular information for quick reference, not narrative articles.
Astronomy
Biology
Medicine
Chemistry
- Periodic Table of the elements
- Table of standard electrode potentials
- Functional groups
Geology
Mathematics
Physics
Size, Measurement and Conversions
Computing
Communications and Internet
Banking and Finance
People (rulers)
People (not as rulers)
- Biographies
- Biblical figures
- Saints
- Nobel Prize winners: Physics, Chemistry, Medicine, Literature, Peace, Economics
- Famous gay lesbian or bisexual people
- Listing of noted atheists
- Listing of noted agnostics
- Listing of noted Buddhists
- Listing of noted Deists
- Listing of noted Hindus
- Recent celebrity deaths