There is a great wealth of chess material at Wikipedia that is worth exploring. Thanks to the "categories" feature you can explore areas of interest. Here are some of the categories I think you'll find useful and interesting:
- Chess books A short list of the most famous books on chess.
- Chess checkmates Links to articles on checkmate patterns that are so common they have names.
- Chess games A short list of the most famous games of chess.
- Chess magazines A list of chess magazines.
- Chess openings A comprehensive listing of the articles pertaining to chess openings.
- Chess organizations A list of the major chess organizations.
- Chess players A list of well-known chess players.
- Chess tactics A good summary list common chess tactics.
- Chess traps A list of the most notorious chess traps.
- Chess terms Links to articles covering a large variety of chess terms.
- Timeline of chess A fascinating chronological list of chess history.
- World records in chess Another interesting short list of chess records.
If you need a master index look here:
- List of chess topics Something in this list from the incredible amount of chess material at Wikipedia will catch your eye.
Wikipedia is a great chess resource - use it to learn and improve.