Gold Hub an excellent range of data and research tools for gold investors. Data sets include gold supply and demand, ETF holdings, central bank reserves, and gold performance analytics.
Gold Stock Data provides financial and resource data for over 700 gold and silver stocks. (Free and paid content)
Did the system collapse? provides up to date charts of the physical gold premium over spot and the physical silver premium over spot.
Priced in gold provides a huge array of charts showing various assets and commodities priced in gold (yes, even Big Macs priced in gold!).
Market Index provides information regarding ASX stocks.
Gold Charts R Us is definitely the place to go for precious metals charts. They provide a comprehensive range of comparative information on precious metal indices, indicators & technical analysis methods for evaluating the gold and precious metals sector. (Free and paid content)
Commitment of Traders Report The COT reports provide a breakdown of each Tuesday’s open interest for markets in which 20 or more traders hold positions equal to or above the reporting levels established by the CFTC. The weekly reports for Futures-Only Commitments of Traders and for Futures-and-Options-Combined Commitments of Traders are released every Friday at 3:30 p.m. Eastern time.
Macrotrends provides a variety of long term historical charts relating to gold and silver.
Long term trends provides interesting and educational charts with rich historical data relating to gold, stocks, real estate and bonds.
Federal reserve economic research provides over 500,000 financial and economic data series, allowing to build and customize charts.